Originally posted by Rogerm60:
Lighter flywheels get rid of some parasitic losses involved in getting the drivetrain to rotate faster. The faster the car, the more the gain. You won't really notice it unless you are running 10's or better.
You are a fool.

You are correct in your explanation of the benefits of lightened flywheels, but to state that you need to be doing 10's to feel it is downright stupid.
The difference is VERY noticable. I bet you've never driven a Contour with a lightened flywheel (yes, I have).
It feels like a serious boost in hp.