Mainly 2kwik is right. However, one thing that should be looked at is the amount of weight each component has. For instance on our cars SVT's have a 20lb. flywheel and the standard V6 has a 22lb. flywheel. The SVT is going to get more power out because it take the engine less time and power to turn the flywheel over. Hence, buying an aluminum driveshaft for a Mustang allows more power to be transmitted to the ground because it takes less rotational force to turn over the driveshaft so more power is transmitted through. Mostly it's weight that drags down the engine. Now imagine how much power we can make if we could make, and get to the ground if every internal and external engine component out of the lightest material possible. That's how some cars make 10,000+ RPM and make a large power band.
