with no primary cats you will experience roughly +30whp through out the power band. however you will also experience better drivability, smoother feel, no bucking, (if DCT) and have the option of removing the cold start, raising the RPM to 8600, ability to turn off certain cell lights, and remove the speed limitation. All do about the same but IMO-BPM is pretty damn good. however, All the others are great too!!
