Appellants, Wilfredo and Julio Rodriguez, appeal their convictions and sentences for various drag related offenses.

Following the five-day trial, the jury returned a verdict of guilty against Wilfredo on Counts 1-6 and against Julio on Counts 1-3. The court sentenced Julio to life imprisonment on Count 1 and 240 months imprisonment on Counts 2 and 3, to be served concurrently, followed by concurrent ten-year terms of supervised release and a $300 special assessment. The court sentenced Wilfredo to life imprisonment as to Counts 1 through 4 and 6, to be served concurrently, and to life imprisonment on Count 5, to be served consecutively to the other counts, followed by concurrent five-year terms of supervised release and a $600 special assessment. Appellants timely appealed.

The issues presented for appellate review are (1) whether the district court erred in admitting co-conspirator statements under Fed.R.Evid. 801(d)(2)(E); (2) whether the district court abused its discretion by admitting evidence of appellants’ prior convictions pursuant to Fed. R. Evid. 404(b); and (3) whether the appellants’ sentences were in error in light of United States v. Booker, 543 U.S. 220, 125 S. Ct. 738, 160 L.Ed.2d 621 (2005).

Whether a statement was made during the course and in furtherance of a conspiracy under Fed.R.Evid. 801(d)(2)(E) is a factual determination that will be disturbed only for clear error. United States v. Lampley, 68 F.3d 1296, 1300 (11th Cir. 1995). A district court’s decision to admit evidence of a prior conviction under Fed. R.Evid. 404(b) is reviewed by this court under an abuse of discretion standard. United States v. Hogan, 986 F.2d 1364, 1373 (11th Cir. 1993). When, as here, a defendant raises in the district court an objection to the constitutionality of the guidelines, preserving a Booker claim, this court reviews the case de novo but will reverse and remand only for harmful er *902 ror. United States v. Paz, 405 F.3d 946, 948 (11th Cir. 2005). “ ‘To find harmless error, [this court] must determine that the error did not affect the substantial rights of the parties.’ ” Id. (quoting United States v. Hernandez, 160 F.3d 661, 670 (11th Cir. 1998)); see also Fed.R.Crim.P. 52(a) (providing that “[a]ny error, defect, irregularity, or variance that does not affect substantial rights must be disregarded”).

Although it is a close question whether the district court erred in admitting the co-conspirators’ statements under Fed. R.Evid. 801(d)(2)(E) and in admitting evidence of appellants’ prior convictions pursuant to Fed.R.Evid. 404(b), we cannot say that the district court committed reversible error. Additionally, we see no Booker error in appellants’ sentences.

Accordingly, after reviewing the record, reading the parties’ briefs, and having the benefit of oral argument, we affirm appellants’ convictions and sentences.

AFFIRMED.