Depends on what track you're talking about. At a venue like Daytona, where brakes are virtually useless and you're running at top speed all around the track, I think our old friend Viper has it. I also believe that it would dominate a road course with an extremely long front straight like Nurburgring or Watkins Glen in which top speeds are easily reached. In both courses, at the end of this straightaway is a tight corner that a Viper can zip around at high speed. Fast-forward a few thousand miles to a more tightly bunched road coarse or even the half-mile oval at Martinsville, and I'd say the Vette has it. I am not implying that Vipers don't handle well around tight corners, which is, in fact, a category where they have an edge. I do, however, believe that Z06 Corvettes accelerate a tough faster, which is essential on short straights where the tall gears of Vipers don't allow as quick of a giddy-up. See? It all depends where you're racing.
Hope schmope. I'll shove a watermelon up my dick and broadcast it all over the internet if good ole Viper doesn't thoroughly rip, tear, chew, and slice the schlong off the Z06 after its 2003 redesign. Sources say it is expected to weigh about 300 lbs less and be available for about $60,000. That's a considerable drop in price, bringing it back to its old bang-for-the-buck character. When the C6 debuts, however, look for quite a showdown and for the cars to be pretty much equal. The horsepower wars are back, baby!
I'd honestly rather have a Viper for (IMO) its agressive beauty; cleaner, more voluptuous lines, and front fascia that's scary enough to make you piss your trousers. Which is the all-around better car, though? In terms of overall performance, Z06 reigns, if only by a nose in acceleration, price, and everyday comfort and drivability.
As previously mentioned, expect a vicious bathroom brawl when Dodge rolls out its faster, lighter, cheaper, and more liveable Viper and Chevy answers the bell with a kick-*** Corvette.