I wouldnt cower, I think itd be a close race with a *STOCK* GT500 with a decent driver maybe giving the 500 the edge. Think a pro driver got a BEST of 12.2. Most of the people that are buying them right now are rich SOBs that prolly cant drive no where near those times, so say anywhere from 12.5-12.8 or worse. Im running 12.8s spinning baddly I know I got 12.6s in it with a better tire. So I think it would be a good race. From a roll it would prolly walk me though.
Also forged internals are going in this winter I say bring it to the GT500s.