I have decided to not track my GT anymore for several valid reasons. I looked at an 01 ZO6 with 850HP as a replacement, asking 40k. Considered an older Porsche Turbo as well. See video below, iniput appreciated.
http://www.youtube.com/watch?v=MaZARqdiDCM
PM me with a phone number and I can put you in contact with a friend that has a very similar set up. I think this is one of Andy's kits/creations from A&A corvette in Ventura, Ca. You can look him up and speak directy with Andy on what you woul duse th ecar for. Give him the link so he can see it. He is a straight shooter.
As for the C5 Zo6 as a track car. It may be the best value at the high end. I have over 6,000 very hard track miles on mine and crew for a T1 guy. They are reliable and predictable, easy to drive at the limit. Parts are pretty cheap. I will note that I have yet to be beat by a C6 Z at the track, I guess most owners are not willing to drive them that hard yet.
My Friend has both the Supercharged Z16 like in the vid and the New C6 with bolt on's. The C5 blower car is faster, not by a lot, but faster. We have run them side by side on testing, him in one and me in the other and vise versa. All roll ons from 50 ish. Gearing is stock in both.
BTW the tires he is tearing up in the vid look like Nitto R2's.
Personally I like N/A cars as track cars. But there was a guy running a Whipple style blower on a C5 at Laguna Seca I ran into. He was much faster through the straight parts. He could not use all the power on corner exit though. Tire limited.
I can tell you about replacement parts and intervals we use for the T1 car if you would like.