10,000mi of abuse on my Fidanza/ACT 2600 combo and loving it! The fidanza flywheel is a very robust piece. Not sure where youre getting the idea that they are of shoddy construction???
http://kentallman.com/paul/91%20Colt/Parts/fidanza1.jpg
http://kentallman.com/paul/91%20Colt/Parts/fidanza2.jpg
http://kentallman.com/paul/91%20Colt/Pa ... ywheel.jpg
Solid 6061 billet hub, replaceable steel friction surface, SFI approved, 8lbs.
I noticed a nice difference (seat of the pants) in the top end, and it revs up a bit quicker. No real driveability issues noted, probably because the KM210 has steep gearing and the car is fairly light.