I have been autocrossing since 87. From 96 til last year it was in Corvettes. From Sept 2002 it has been in a GTS, with some other experience in a ASP RT/10 that a friend runs down here. I can tell you that a Corvette does have better pure handling characteristics, it brakes, turns and accelerates wonderfully in stock trim. A Viper in stock trim has some problems that limit them from handling better in stock trim. One is the front outer-to-outer rim width versus the rear outer-to-outer rim width (the measurement taken from outer edge of the rims). The front is much narrower than the rear, which makes the car want to go straight, this is one of the reasons it puts power down so well. Another factor is the cars weight, it is much heavier than a Z06. I tried running the GTS in Stock trim for autocross, I ran 17" stock 96 rims on my 02, because it isn't my car, and I can't afford to run 18" Hossiers. I run on some very fast courses, and on those fast courses I was the car to beat, I would run as fast as street prepared(driven by a few national champions). On the slow courses, the car was like a battle ship, it just wanted to bull doze its way around slow corners (this was on stock width 17x10f and 17x13r with Kumho Ecsta's) A Z06 handles very well and stops with some authority, and is much quicker out of slower corners(it has a very short 2nd gear).
Having driven a very well prepared ASP 96 RT/10, I gave up on trying to run the GTS in stock. I knew the car could handle very well if the defficiencies were dealt with, and I was right. We put 17x12" CCW's with 335 Kumho Ecstas all around, and it turned it so much better. It didn't push the second I turned the wheel with the bigger tires. Last weekend at the San Diego SCCA Solo II national tour was the first time on the big wheels and tires. I took a gamble on the big change, because I had to do everything I could to try to catch the current national champion in ASP. It will be a car to contend with on our fast courses, but I will need to change my alignment to compliment the cars new found front grip. The car use to put power down so hard that I couldn't get the back end loose, even in first gear. Let's just say it gets loose now, and how. I have been running 0 total rear toe, which worked great with the stock set up, but won't cut it any longer. We have another event in 2 weeks and I will put in a bunch of toe-in to help the car put the power down again. If it works it will be very fast, even though it is still a stock car with just big wheels on it.
I will say this about quality of both cars. The Vipers paint is the nicest of any car in America, almost of any car in the world. I have seen a lot of very high end cars and paint jobs and this one stands with the best of them. The paint on the Z06's I have seen has been very poor for such an expensive car. The interior on both is sub par, with comfort going to the Corvette. It looks like they designed the fastest car in the world, then had to figure out a way to put an interior after the fact on the Viper.
Let's face it, both cars have a cult like following, and each have their place. I am a vette fanatic(C4's) and will get another one some day, they are great bang for the buck. The Viper looks bad ***, and kicks some major ***** when you mash down on the go pedal. Slap some huge front wheels on it, and it will handle like a dream.
SoloIIRacer