Well, if a car jumps the other car by about a car...the amount of ground that will have to be made will be considerable...because the other car has already began accelerating before the other car...it is not as simple as say both cars starting exactly at the same time with one car difference...makes sense?
If an 06 Viper is one car ahead before both cars punch it, the Z will pass it in no time. If the 06 Viper punches it and the Z punches it AFTER the Viper is already one car ahead, the ground that will have to made up will be much much more as the Viper had already began accelerating before...I am sure there is a way to calculate this exactly but thinking about it already gives me a headache...LOL.
I don't know why the 08 Viper was brought into the equation as your question was about a GenIII so I will stick to that (as I have a gen IV Viper and THAT is a driver's race against a C6Z06, no matter what anyone tells you).
So...on the road course, which again, seems the question at hand, yes, if you are running consistent times than the Z06, you ARE a better driver...and you have every reason to throw it on Z06 driver's face...
Z06's brakes will overheat sooner or later, especially if you are very aggressive on the braking (raises hand). If the driver of the Z is much smoother the brakes will last a LONG time. A lot of Z's switch to dot4 and more aggressive pads, but the biggest complaint is that the cooling ducts are too far from the actual rotors/brakes, so a lot of them also insert ducts that accomplish much more efficiency when cooling.
The runflat's are crap on the Z...however, they are extremely predictable and also do not overheat as quickly as the "stock" tires on the Viper. The runflats also have very stiff sidewalls which is very helpful on the roadcourse...but the grip would be the advantage on the Viper.
Have fun on course and be safe...