Got lucky(in this boring-ass tourist paradise) and found myself at a stop next to an LS1 in 320hp mode (Camaro SS). I heard his pipes, looked over and said "I know that ain't stock". He said all he was running was an exhaust, but a nice one. High flow X pipe setup, not sure 'bout the headers. I think those trims gain a fair bit of HP from aftermarket exhaust, but dunno the exact figures. So he was probably running from 330-345 crank HP to my 300 ('05 GT). I asked if he wanted to go and he said "Sure, let's see who's heavier". True enough. Interestingly, I pretty much had him off the line, even though my stock rubber was going to glass mode well into 2nd. But at the top half of 2nd he really caught a big breath and surged ahead. Not by a huge margin, but he clearly won by 3rd. I was actually really happy with my stang, knowing the numbers. One thing I'm curious about, though, is as he said, the weight. I know my buddy's LS1 Firebird weighs like a hog: 4200 something. considering I'm a good 400 lbs lighter, I'm thinking it's still a pretty even match-up.