[legion]

Your numbers are old.

1) 0% is made from the real production car. They all run the same spec chassis called the COTM.
2) NASCAR is looking into fuel injection. Understand that changing this would be a HUGE change to the teams and a huge change to how the rules are applied. It's much easier to look for cheats in a mechanical device than in software.
3) Most racing series use some form of restricted intake to limit horsepower. ALMS and WRC come to mind. Other series run a stock engine or limit displacement. Either way, the intent in the same: to limit top speed from exceeding driver reaction time.
4) ALL race series have minimum weight requirements.

That said, there is a lot of real engineering that goes on in NASCAR. They have figured out how to get 900+ hp out of a pushrod V8 and how to get it to rev to 9,000 rpm. These guys study every rule in detail and look for any wiggle room possible. It's widely believed that most of the teams have figured out how to implement a form of traction-control through the ignition system.