I plugged in the coefficient of drag and the frontal area of the Z, and looked at the figures. I don't have the exact numbers offhand, but to do 100 mph you need about 80 hp, to do 200 mph you need 500+ hp, and to do 300 mph you'd need something like 2000 hp. That car that broke the sound barrier at 740 mph had something like 60,000 hp.