Me and my buddy did one for kicks, Not to really see whos louder, we were both equal pretty much, but to hear the sound difference with both trucks. He had a 03 Chevy Z71, hi-flow cats, 2.5" duals no cross over, Super 40 mufflers, 4x18 tips 45'd. The video is on my youtube, there a bit of profound language so I wont post it on here since we cant post video links without it popping up as a video anymore..