G37? No thanks.
Definately the G8, i've grown to like em quite a bit, almost as much as a GTO. Can't go wrong there either. Both cars FTW.
If you don't need the passenger space I say a good used C5 then throw on a set of heads, cam, headers, catback, gears, stall, and a set of slicks and have some real fun. That was my plan for possibly next summer. Now with a few life changing plans, that will have to wait a little while longer. Some day I'll have one though, and a buddy to enjoy it with me too.....