Defendant Damion Townsend (“Defendant”) appeals from his conviction for conspiracy to distribute, and possess with intent to distribute, fifty grams or more of cocaine base (“crack”), and an unspecified amount of cocaine, in violation of 21 U.S.C. §§ 841(b)(1)(A), 841(b)(1)(C), and 846, entered by the United States District Court for the Southern District of New York (Keenan, /.). We assume the parties’ familiarity with the facts, procedural history, and scope of the issues presented on appeal.
I. Sufficiency of the Evidence
Defendant argues that there was insufficient evidence to support his conviction. Specifically, Defendant contends that the Government’s key witness was not credible, that there is no evidence that Defendant planned the drug transaction, and that there is insufficient evidence that De*140fendant was a knowing participant in any illegal conduct and rather that he was just an innocent man driving his friends around.
A. Standard of Review
A defendant challenging the sufficiency of the evidence underlying a criminal conviction bears a “heavy burden,” because this Court “must review the evidence in the light most favorable to the government, drawing all reasonable inferences in its favor.” United States v. Gaskin, 364 F.3d 438, 459 (2d Cir.2004). “Reversal is warranted only if no rational factfinder could have found the crimes charged proved beyond a reasonable doubt.” Id. at 459-60. “In other words, a court may grant a judgment of acquittal only if the evidence that the defendant committed the crime alleged was nonexistent or ... meager.” United States v. Jackson, 335 F.3d 170, 180 (2d Cir.2003) (internal quotation marks omitted) (omission in original).
B. Discussion
In light of this highly deferential standard of review and the evidence proffered against Defendant, this ground of appeal is meritless. The record includes evidence that Defendant had a relationship with an alleged co-conspirator, Ismaiyl Jones, discussed a drug sale with co-conspirators, drove his co-conspirators around as they planned a drug sale and picked up drugs, went with Jones to pick up cocaine, and helped to turn the cocaine into crack.
Defendant argues that the case against him all depends on Jones being a credible witness and contends that Jones was not credible. To be sure, a great deal of the Government’s case relies upon Jones’ testimony, and because Jones was a paid informant and cooperator, one might reasonably question his credibility. But that does not warrant an acquittal on appeal. For one thing, much of Jones’s testimony was corroborated by eyewitness accounts from law enforcement officers, transmissions heard by a DEA agent, physical evidence, and recordings. Moreover, it is not for us to evaluate the credibility of a witness, a task better left to the jury. See United States v. Thompson, 528 F.3d 110, 119 (2d Cir.2008) (per curiam). The jury that saw Jones testify voted unanimously to convict, and we must accordingly draw all inferences, including inferences as to credibility, in favor of conviction.
Defendant also makes two slightly more specific and related points, that there is no evidence that Defendant planned the drug transaction, and that there is insufficient evidence that Defendant was a knowing participant in any illegal conduct and rather was just an innocent man driving around his friends. Neither of these arguments, however, have any merit. It is necessary that there be evidence that Defendant “knew of the existence of the scheme alleged ... and knowingly joined and participated in it.” United States v. Rodriguez, 392 F.3d 539, 545 (2d Cir.2004) (internal quotation marks omitted). It is, however, in no way necessary that Defendant have planned the encounter. And there is ample evidence that Defendant’s non-planning role was a knowing role. Defendant discussed drug prices, details of a drug transaction, and helped convert cocaine to crack. Defendant contends that this is not enough to support a finding of knowledge on his part. But given our precedents, that argument is unavailing. See, e.g., United States v. Nusraty, 867 F.2d 759, 764 (2d Cir.1989) (listing factors that distinguish innocent conduct from knowing participation in a conspiracy).
II. Admission of Prior Bad Acts Evidence
Defendant further argues that the District Court erred by admitting evidence of *141prior firearms sales, in violation of Rule 404(b) and Rule 408.
A. Standard of Review
We review evidentiary rulings for abuse of discretion. United States v. Lombardozzi, 491 F.3d 61, 78-79 (2d Cir. 2007) (Rule 404(b) determination); United States v. Salameh, 152 F.3d 88, 110 (2d Cir.1998) (per curiam) (Rule 403 determination). “To find such abuse, we must conclude that the trial judge’s evidentiary rulings were arbitrary and irrational.” United States v. Paulino, 445 F.3d 211, 217 (2d Cir.2006) (internal quotation marks omitted). Furthermore, evidentiary rulings are subject to harmless error analysis. Fed.R.Crim.P. 52(a); United States v. Jackson, 301 F.3d 59, 64 (2d Cir.2002). “An erroneous ruling on, the admissibility of evidence is harmless if the appellate court can conclude with fair assurance that the evidence did not substantially influence the jury.” Jackson, 301 F.3d at 65 (quoting United States v. Rea, 958 F.2d 1206, 1220 (2d Cir.1992)).
B. Discussion
The Federal Rules of Evidence prohibit admission of “[ejvidence of other crimes, wrongs, or acts ... to prove the character of a person in order to show action in conformity therewith.” Fed. R.Evid. 404(b). The Rules, however, do permit such evidence “for other purposes, such as proof of motive, opportunity, intent, preparation, plan, knowledge, identity, or absence of mistake or accident.” Id. To determine whether a district court properly admitted other act evidence, we consider whether “(1) the prior acts evidence was offered for a proper purpose; (2) the evidence was relevant to a disputed issue; (3) the probative value of the prior act evidence substantially outweighed the danger of its unfair prejudice; and (4) the court administered an appropriate limiting instruction.” United States v. Brand, 467 F.3d 179, 196 (2d Cir.2006) (internal quotation marks omitted). In so doing, we take an “inclusionary approach.” United States v. Lasanta, 978 F.2d 1300, 1307 (2d Cir. 1992).
The District Court did not abuse its discretion by admitting the prior bad acts evidence. That evidence now at issue was relevant and highly probative as to knowledge and intent, both of which were disputed. It showed the development of the relationship between Defendant and Jones, “providing] background for the events alleged in the indictment” and “enabling] the jury to understand the complete story of the crimes charged, or how the illegal relationship between coconspirators developed.” United States v. Reifler, 446 F.3d 65, 91-92 (2d Cir.2006) (internal quotation marks and citations omitted) (alterations omitted). That is especially true in a case, such as the one now before us, where the prior dealings between two conspirators show “the basis for the trust between” the co-conspirators. United States v. Brennan, 798 F.2d 581, 590 (2d Cir.1986). It is also especially applicable in this case where, as Defendant strenuously argues, some of the observed conduct might be nothing more than innocent acts of a friend, and not a knowing participation in a conspiracy. Driving two friends around town might, for example, seem innocuous. See Nusraty, 867 F.2d at 764. Prior gun sales, however, at least suggest that Defendant was not an innocent pawn taken by surprise by the drug transaction. The evidence was also accompanied by a careful and thorough instruction limiting the evidence to relevant Rule 404 grounds. That instruction was delivered on several occasions during testimony as well as in clear jury instructions on the issue. In light of the purpose and value of the evi*142dence, and of the limiting instructions, we find no abuse of discretion in deeming the evidence admissible under Rule 404.
Defendant further argues that even if this evidence was properly admitted under Rule 404, it should have been excluded under Rule 403. Under Rule 403, “evidence may be excluded if its probative value is substantially outweighed by the danger of unfair, prejudice, confusion of the issues, or misleading the jury.” Fed.R.Evid. 403. As discussed above, the prior gun crimes were probative insofar as they established the history of the conspiracy, trust between the parties, intent, and knowledge. Indeed, they were especially probative insofar as one of the three charged counts involved possession of a firearm. The nature of Jones and Defendant’s friendship was very much at issue at trial, and now on appeal, insofar as Defendant argued, and continues to argue, that they were mere friends and Defendant’s assistance in any criminal activity was done without his knowledge.
To be sure, the admission of any evidence not directly related to the charged conduct has the potential to be prejudicial. But it does not appear that prejudice here was likely to be great. Gun transactions are not especially worse or shocking than the transactions charged. And the District court gave several careful instructions to the jury regarding what inferences it could draw from the admitted evidence. See, e.g., Paulino, 445 F.3d at 223; United States v. Snype, 441 F.3d 119, 129-30 (2d Cir.2006) (noting that “the law recognizes a strong presumption that juries follow limiting instructions”).
The District Court had first hand exposure to the witnesses, jury, and other evidence, giving it a “superior position to evaluate the likely impact of the evidence.” Li v. Canarozzi, 142 F.3d 83, 88 (2d Cir. 1998). There is no good reason for us to second guess that determination in this case. Moreover, in the case before us, Defendant’s arguments to the contrary notwithstanding, the evidence was very strong. We conclude, therefore, that even assuming the District Court erred, any such error was harmless.
III. Conclusion
We have reviewed all of DefendanWAppellant’s claims and find them meritless. Accordingly, the judgment of the District Court is AFFIRMED.