Ya know I really didn't see a huge difference that I can attribute to the flywheel alone. Then again, I went from a burnt out clutch to an ACT clutch and lightened flywheel. The difference was night and day, but since I did both the clutch and flywheel at the same time, it's hard to tell which contributes the most. I can tell you one thing though, I can sure rev up quicker, so having less mass there does help.