| I haven't heard too many that I like in person. But then I like it quiet for cruising. I like the stock exhaust best, but then with headers it kinda doesn't sound right. The only one I've heard in person that I am REALLY fond of, that had headers, was an '05 with Kook's LTs and a magnaflow cat-back. This one sounded just like a stock car at idle, pulling through the lanes (it was at the track by the way) it had the same tone as a stock car, just a little louder, and at WOT it sounded great as well, very aggressive, but it didn't pop or anything.
But nothing beats WOT with longtubes and cutouts on an LS1 (or LS2)!! | 
Linear Mode
