"As far as the nitro cars go these rockets are breaching sanity and that's their primary draw. You start taming them then their popularity will dwindle."

I can't see it. Most folks who watch them like the smoke, the flames, the ground pounding. Back in the day, the fields with five second passes and 270 mph speed offered the same thrill, and, at least as good if not better, show. And, there were more of them. Slow them all down, and no one would notice the difference. You'll still have the same sensory experiences, and even more cars.