I've had one actual race/hunt, against a 2001 WS6 Trans Am, from about 60-120. We were both neck and neck until I went to 4th gear (at about redline), then he actually started pulling away from me. At about 120 he was about 2 car lengths ahead. We later stopped and chatted, he claims he has no mods at all on his T/A and it had 128,000 miles on it. Gotta give credit where credit is due - those LS1s are really something (I should know, I've had 3 of them).
About a month ago I had a guy challenge me in a G8 GT, but the guy was acting like a total idiot and I didn't trust him (plus it was at night and traffic was way too heavy).
I did get to one place where I was able to take it up to 140 - it felt like I could have gone faster but I felt like I'd already pushed my luck enough.
