This silly, what do you want to beat them in, off-road rally racing, around the Nurburing, 1/4 mile track, down the Rubicon trail? Seriously, to have any meaning posts like this need to specifically mention what is being compared. I'm guessing you want to compare straightline speed, in which case the Camaro SS should beat anything else under $40k, and the only cars that won't at least be reasonably close to are supercar types. The GT500 specifically should definately be faster straightline but it won't be as comfortable as the GT500 driver would like.
Around a track the GT500 could very easily be the slower car. We really don't have solid numbers yet so don't get to excited either way. If you really want to compare theoretical numbers though 0-60 numbers are about the worst choice, 0-60 can give you some idea of how fast a car is but 1/8 and 1/4 times will give you a much better idea of how fast a car is.