Ernest Cortinas, Ricardo Rodriguez, Henry C. Villegas, Daniel Chavez Villegas, Johnny Albert Martinez, Linda Rodriguez Mata, and Eric Wayne Green were convicted of conspiracy and various substantive offenses arising out of a marihuana distribution enterprise. They challenge on appeal, inter alia, the admissibility of certain evidence, the denial of various motions to sever, the sufficiency of the evidence, and the trial court’s sentencing findings as to the amount of marihuana involved in the offenses. For the reasons assigned, we affirm in part and vacate and remand in part.
*246BACKGROUND
The appellants’ convictions are related to a drug smuggling organization headed by Daniel Nieto. In 1984, Nieto began storing marihuana at Metro Transmissions, his place of business in San Antonio, and eventually expanded his involvement in the drug trade to become a major distributor of marihuana between San Antonio and Saginaw, Michigan. Nieto bought marihuana from Arturo Villareal which was delivered to Metro Transmissions by Rodriguez, Villareal’s uncle. On several occasions members of Nieto’s organization paid Mata, Villareal’s sister, for the marihuana. The relationship between Nieto and Villareal ended in 1989 and Nieto acquired another marihuana source.
As his operations grew, Nieto hired a number of people, including Martinez, to transport the marihuana, using Dan’s Paint and Body Shop, a San Antonio business, as a front. Employees of Dan’s would fit vehicles with concealed compartments, do touch up paint and body work to conceal the compartments, and load and unload marihuana. Henry Villegas was the owner and Daniel Villegas was an employee of Dan’s. Both were members of the Southsiders Bikers Club, a boot camp organization for the Ban-dido Nation Motorcycle Club.
In 1989, encountering problems collecting from some Michigan customers, Nieto enlisted the services of Cortinas, a small-time customer, and other members of the San Antonio Chapter of the Bandido Nation Motorcycle Club to assist in the collection effort. In the process of collecting one such account, in September 1991 Cortinas and fellow Bandido members Edward Salas and Green, reportedly “shot up” the house of a delinquent debtor. The shooting resulted in the death of a 14-year-old boy. The house was under the “protection” of a Michigan motorcycle club, the Outlaws, and in order to prevent retaliation the Bandidos obtained $25,000 from Nieto to give to the Outlaws. Nieto testified that the Bandidos eventually took over his business and that he acquiesced in that takeover because he feared for his life and the life of his family.
Nieto was arrested in May 1992 along with several confederates. Nieto and others plea bargained for reduced sentences in return for information and testimony against other members of the organization. In January 1995, 28 members of Neito’s organization were indicted for conspiracy with intent to distribute marihuana, in violation of 21 U.S.C. § 841(a)(1) and § 846, and various other substantive offenses. A jury found all appellants guilty on the conspiracy count.1 Mata was also convicted of conspiring to launder drug money proceeds in violation of 18 U.S.C. § 1956. The jury acquitted Martinez of conspiring with Edward Jesse Rodriguez2 to distribute marihuana. The appellants timely appealed.
ANALYSIS
Appellants assert the following claims of error: (1) the district court abused its discretion in admitting evidence of the Bandido’s methamphetamine trafficking, the Michigan shooting and the Bandido’s tactics and philosophy; (2) the district court erred in refusing to sever the trials of Rodriguez, Mata, Henry Villegas, and Daniel Villegas; (3) the evidence was insufficient to support the convictions of Cortinas, Rodriguez, Daniel Ville-gas, Martinez, Mata, and Green; (4) the district court abused its discretion in denying Cortinas’ request for an alibi jury instruction; (5) the government gave Cortinas and Green inadequate notice of its intention to seek an enhanced penalty under § 841(b) which constituted a denial of due process; (6) the quantity of marihuana for which Cortinas was held accountable was not properly determined; (7) the district court erred in enhancing Cortinas’ sentence based upon his alleged leadership role in the conspiracy and for possession of a firearm; and (8) Henry Ville-gas’ trial counsel rendered ineffective assis-*248The government introduced evidence of the debt, the shooting, and the results of the Mount Morris Police Department’s investigation which led them to conclude that Corti-nas, Green, and Salas were the gunmen.
Appellants contend that the district court abused its discretion in admitting this highly inflammatory and potentially prejudicial evidence. Although the district court did not allow evidence of the death that resulted from the shooting, appellants maintain that the testimony implied, and in fact led the jury to believe, that someone was killed in the incident. We are not persuaded.
The shooting incident was admitted properly as an intrinsic act in furtherance of the conspiracy.9 The violence was part of the effort to collect money owed for marihuana that had been delivered to one of Nieto’s customers. Additionally, and most importantly, any undue prejudice was avoided by disallowing evidence of the death of the 14-year-old boy. The court’s admission of this evidence was not error.
Appellants who were not members of the Bandidos10 contend that even if this evidence was properly admitted as to those involved in the incident, the district court failed to craft an adequate limiting instruction to preclude the jury from considering that evidence as to them. The appellants, however, did not object to these instructions as being erroneous or inadequate, nor did they propose that other, preferable limiting instructions should have been given. We, therefore, may review only for plain error.11 We find none.
II. Severance
Prior to trial, Rodriguez,12 Mata, and Henry and Daniel Villegas filed separate motions for severance under Fed.R.Crim.P. 14, contending that much of the evidence that would be introduced at trial was irrelevant and so highly prejudicial to their case as to undermine their right to a fair trial. We review denial of a Rule 14 motion for an abuse of discretion.13 The appellants must show that they “suffered specific and compelling prejudice against which the trial court was unable to afford protection, and that this prejudice resulted in an unfair trial.”14
Rodriguez and Mata contend that they were prejudiced by the testimony of the Bandido’s tactics and activities, including the highly inflammatory evidence of the Michigan shooting. Although “persons jointly indicted in a conspiracy case should generally be tried together,”15 we must conclude that Rodriguez’ and Mata’s motions for severance should have been granted. Neither Rodriguez nor Mata was associated with the Ban-didos. In fact, the record reflects that then-charged involvement with Nieto ended in 1989, prior to the Bandido’s joining the conspiracy. After 1989, Nieto obtained another source of marihuana and no longer used Vil-lareal, Mata’s brother and Rodriguez' uncle, as his supplier.16 Limiting instructions given by the trial judge were inadequate to mitigate the prejudicial effect of the overwhelming testimony regarding the violent, criminal activities of the Bandidos. Accordingly, the convictions of Rodriguez and Mata are vacated and as to them, the matter is remanded to the district court for further proceedings consistent herewith. *247tance. We consider these issues in that order.
I. Admissibility of Evidence
Several of the appellants contend that some of the evidence presented at trial was inadmissible. They properly objected at trial, preserving error on these points, and we review applying the abuse of discretion standard.3
A.Methamphetamine Trafficking
Cortinas and Green complain about the admission of testimony by Jay Lane Roberts, a Bandido National Officer, that he periodically sold to them methamphetamine in quantities sufficient for resale.4 The admissibility of extrinsic evidence is governed by Fed.R.Evid. 404(b) which allows the introduction of such evidence for purposes other than to show that the defendant acted in conformity therewith. Interpreting that rule, we have applied a two-step test. “First, it must be determined that the extrinsic offense evidence is relevant to an issue other than the defendant’s character. Second, the evidence must possess probative value that is not substantially outweighed by its undue prejudice and must meet the other requirements of rule 403____”5
This evidence was admitted properly under Fed.R.Evid. 404(b) and 403. The extraneous drug evidence, trafficking in methamphetamine, necessarily entails the same knowledge or intent to traffiek in marihuana, the controlled substance at issue herein. Furthermore, we previously have held that “proof of prior drug activities is more probative than prejudicial.”6 The district court did not abuse its discretion in admitting this evidence.7
B. Bandido’s Tactics and Philosophy
Cortinas, Rodriguez, and Martinez contest the admission of general testimony about the culture, activities, and tenets of the Bandidos. Roberts described the “gang” as being into “motorcycles and crime. Mainly methamphetamine, ... stolen motorcycles, prostitution, strong arm, theft, drugs, [and] violence.” He explained that the gang associated with “characters”—successful, non.member criminals—and attempted to take control of their criminal enterprises and money. This testimony illustrated the “talents” of the Bandidos that led Nieto to employ the organization in his debt collection efforts. Additionally, it supports the reasonable inference that members of this gang could form the requisite intent to engage in an illegal enterprise. Thus, the district court did not abuse its discretion in admitting this testimony.
C. Michigan Shooting
In 1991, Frances O’Valle, one of Nie-to’s Michigan customers, owed Nieto for marihuana that had been “fronted” to her.8 Nieto employed the Bandidos to collect this debt. O’Valle told of difficulties she was experiencing collecting from a customer and complained to Nieto about the debt collectors’ strong arm tactics. Nieto promised O’Valle that she would be left alone if she would give the address of her delinquent customer, one Forest Zudell. The address was given and Zudell’s house in Mount Morris Township, Michigan was “shot up,” and a 14-year-old boy was killed. The police investigation determined that the shots had been fired by three gunmen from three different angles. The government maintained that Cortinas, Green, and co-defendant Salas were the three responsible for the shooting.
*249Henry and Daniel Villegas also contend that they were prejudiced by the Bandi-do evidence. The evidence showed, however, that both were members of the Southsiders Motorcycle Club, a boot camp organization for the Bandidos. Their alleged involvement with Nieto coincided with the Bandido collection efforts. Our review of the record persuades that the trial judge did not abuse his discretion in refusing to sever these defendants.
III. Sufficiency of the Evidence
All appellants, with the exception of Henry Villegas, contend that the evidence was insufficient to support their convictions. In reviewing such challenges we view the evidence in the light most favorable to the jury’s verdict and affirm if a rational trier of fact could have found that the government proved all essential elements of a crime beyond a reasonable doubt.17 Credibility determinations and reasonable inferences are resolved in favor of the jury’s verdict.18
Cortinas, Daniel Villegas, Martinez, and Green challenge the sufficiency of the evidence supporting their convictions for conspiracy to possess with intent to distribute marihuana.19 Necessary elements of the conspiracy are: (1) the existence of an agreement to possess marihuana with the intent to distribute, (2) knowledge of the agreement, and (3) voluntary participation in the agreement.20 Although mere association or presence alone are insufficient to prove knowing participation in the agreement,21 when combined with other relevant circumstantial evidence these factors may constitute sufficient evidence to support a conspiracy conviction.22
We find that the evidence of record is adequate to support a reasonable inference that each of these appellants were knowing and voluntary members of Nieto’s marihuana distribution enterprise. A National Bandido Officer and Nieto, himself, testified that Cor-tinas worked as a debt collector and enforcer for Nieto. Cortinas was introduced to Nie-to’s customers and associates as an employee, and Nieto’s bookkeeper testified that Cortinas was paid for his services. Additionally, the government’s evidence showed that the Cortinases lived beyond their reported income and evidence found in various searches linked Cortinas to the drug trade.
Daniel Villegas was identified by several witnesses as an employee of Dan’s Paint and Body Shop. Nieto identified Daniel Villegas by his nickname “Gordo”, and testified that he worked on Nieto’s vehicles constructing hidden compartments or doing body work to conceal them. Jesse Hernandez, a cooperating co-conspirator, specifically testified that he had seen Daniel Villegas painting one of the secret compartments. The evidence sufficiently supports Daniel Vil-legas’ conspiracy conviction.
Martinez was a driver for Nieto. Frances O’Valle identified him as the person delivering marihuana to her. Luis Bermu-dez, O’Valle’s son-in-law, also identified Martinez as having delivered marihuana to him. Additional documentary evidence, such as notations in purported drug ledgers and motel receipts from Michigan, supports the involvement of Martinez in the conspiracy.
Green was a member of the Bandi-dos. He accompanied Nieto to Michigan on a couple of occasions and aided Cortinas in the debt collecting. Green was a suspect in the Michigan shooting and a fellow Bandido testified that Green told him that he had received the “TCB” Bandido patch for “taking care of business” in Michigan. The evidence supports a reasonable inference that Green was a knowing and voluntary member *250of the conspiracy. The challenges to the sufficiency of the evidence are rejected.
IV. Alibi Jury Instruction
Cortinas contends that the district court abused its discretion in refusing to give an alibi instruction. He maintains that he presented sufficient evidence that he was at a motorcycle rally in Canyon Lake, Texas over the 1991 Labor Day weekend when the Zu-dell house was attacked. The evidence, however, shows only that Cortinas was last seen at the rally on Sunday morning. The shooting did not occur until the early hours of 'Monday morning and the jury reasonably could infer that Cortinas had time to travel to Michigan in order to participate in the shooting. We find no error in the district court’s refusal to give the requested instruction.
V. Notice of Enhanced Penalty
Cortinas and Green claim a due process violation, contending that the government gave them inadequate notice of its intention to seek an enhanced penalty under 21 U.S.C. § 841(b). This argument is without merit. Each was notified in his Presentence Investigation Report, made available seven weeks before sentencing, that he was subject to an enhanced prison term of ten years to life because the conspiracy involved more than 1,000 kilograms of marihuana, and that the government would be filing a notice of enhanced penalties. A month before sentencing the government gave each formal written notice. There was no due process violation.
VI. Sentencing of Cortinas
A. Quantity of Drugs
Cortinas contends that the district court erred in determining the quantity of drugs for which he was responsible. At sentencing, the district court found that Cor-tinas had participated in the conspiracy for at least 20 months during which the average amount of marihuana moved had been no less than 500 pounds. In a conspiracy case, the drug quantity for purposes of sentencing includes amounts attributable to co-conspirators’ conduct in furtherance of the conspiracy as long as those amounts were reasonably foreseeable to the complaining defendant.23 Drug quantity is a finding of fact reviewed for clear error.24 After reviewing the record, we conclude that the determination of the quantity of drugs for which Cortinas was held accountable was not clearly erroneous.
B. Enhancement
In sentencing Cortinas, the district court assessed a two-level upward adjustment under U.S.S.G. § 2D1.1(b)(1) for possession of firearms in furtherance of the conspiracy and a three-level upward adjustment under U.S.S.G. § 3Bl.l(a) for his leadership role in the conspiracy. Cortinas contends that the evidence did not support such adjustments. We review these adjustments and findings of fact for clear error.25 Finding no such error, we reject this challenge.
VII.Ineffective Assistance of Counsel
Henry Villegas maintained that he received ineffective assistance of counsel during his trial. To succeed, he must prove that (1) his counsel’s performance was deficient and (2) this deficient performance prejudiced his defense.26 We must presume that counsel’s performance was reasonable.27' Henry Villegas maintains that his attorney failed to file a motion to suppress evidence obtained in a search of his business, Dan’s Paint and Body Shop. He also contends that his counsel failed to impeach an important government witness.
Sufficient evidence existed independently of the things obtained in the search to support Henry Villegas’ conviction and a co-*251defendant’s counsel attempted to impeach the government witness with the information of which he now complains. Even were we to find that counsel’s performance was deficient, Villegas’ claim would still fail because he was not prejudiced thereby.
We conclude that all other points of error urged by the parties lack merit and they therefore are rejected.
For the foregoing reasons, we AFFIRM the convictions and sentences of Ernest Cor-tinas, Henry C. Villegas, Daniel Chavez Ville-gas, Johnny Albert Martinez, and Erie Wayne Green and we VACATE the convictions and sentences of Ricardo Rodriguez and Linda Rodriguez Mata and REMAND for further proceedings with respect thereto consistent herewith.
. Of the 27 defendants named in the superseding indictment, ten went to trial: the seven appellants at bar along with Edward Salas, Jesse David Rodriguez and Janet Westover Torrez. Salas was dismissed by the government after it rested. Jesse David Rodriguez was found not guilty, and Torrez, although convicted, is not a party to this appeal.
. Edward Jesse Rodriguez was a fugitive and was not tried.
. See United States v. Maceo, 947 F.2d 1191 (5th Cir.l991)(evidence of an uncharged offense arising out of the same transactions as the offenses charged in the indictment is not extrinsic evidence within the meaning of Rule 404(b)).
. Rodriguez, Mata, Henry Villegas, Daniel Ville-gas, and Martinez were not members of the Ban-didos.
. Fed. R.Crim. Proc. 52(b).
. Rodriguez asserts this error on appeal by adoption.
. See United States v. Restrepo, 994 F.2d 173 (5th Cir.1993); United States v. Toro, 840 F.2d 1221 (5th Cir. 1988).
. Toro at 1238.
. United States v. Scott, 795 F.2d 1245, 1250 (5th Cir.1986).
. The record contains evidence of payments for real estate used by Mata and Villareal in the alleged money laundering scheme that post date 1989. These payments, however, were not tied to the Bandidos' activities.
. See United States v. Speer, 30 F.3d 605 (5th Cir.1994).
. Roberts also testified that at a point in his dealings with Cortinas the relationship changed and Cortinas became his supplier of methamphetamine. He also testified that Green had sold him methamphetamine.
. United States v. Beechum, 582 F.2d 898, 911 (5th Cir.l978)(enbanc).
. United States v. Harris, 932 F.2d 1529, 1534 (5th Cir.1991).
. It should also be noted that the jury was cautioned immediately after Roberts’ direct examination that the evidence of the methamphetamine trafficking could only be considered against Cortinas and Green.
. Marihuana would be delivered to Nieto’s customers who would pay in cash a short time later.
. See United States v. Puig-Infante, 19 F.3d 929 (5th Cir.1994).
. Id.
. Rodriguez and Mata also challenge the sufficiency of the evidence. Because of our decision regarding their motions to sever we do not address their arguments on this issue.
. See United States v. Mergerson, 4 F.3d 337 (5th Cir.1993).
. See United States v. Vergara, 687 F.2d 57 (5th Cir.1982).
. See United States v. Williams-Hendricks, 805 F.2d 496 (5th Cir.1986).
. United States v. Alix, 86 F.3d 429 (5th Cir.1996).
. Id.
. United States v. Rivas, 99 F.3d 170 (5th Cir.1996).
. Pitts v. Anderson, 122 F.3d 275 (5th Cir.1997).
.Id.