found a list of what it took to get the gt500 into the mid 9's.
throttle body, cold air intake, tune, colder plugs, ati crank dampner, little extra boost, headers, 4.30 gears, shell urt fuel. they didn't say what size slicks, but from the pics, they look to be 10.5's, truly stock chassis.
i may have missed something there, but that's a pretty darn small list of bolt ons to get a car to hit mid 9's in the upper 140mph range, and still be weighing around 3800#.