Since each of these cars is built specifically for speed and improved capabilities at a racetrack, we went with the latter. The usual changes include a lowered ride height and stiffer springs, shocks and bushings. All three cars have stiffer suspensions. The Cobra R's changes are the most extensive, though that's expected given the big jump needed to go from a regular Mustang to one that can compete against a Viper.
Fuel cells are much sturdier than regular gas tanks.
The Cobra R was the only car in the test to have one. Lighter wheels and stickier tires go a long way toward improving a vehicle's handling. While the Viper's ACR package includes lighter 18-inch BBS wheels, the tires included are no different than the ones fitted to regular GTS cars. The Corvette Z06 and Cobra R have wider wheels and stickier tires compared to the regular versions of these cars. Less weight improves acceleration, braking and handling.