Be careful,
the Fidanza flywheels on Ebay are for the Twin Cam engine! The one that's for sale on the Yahoo group is one that was custom made in a group buy a couple of years ago. There are some reviews in the KB but the consensus is that it's a really nice upgrade without losing any tractability in our light cars.
The Aluminium flywheels have a steel section for the clutch plate to grab on to if I'm not mistaken, so it wouldn't make a difference.
I'll be going with a custom steel one, maybe a little bit more expensive, but you can get them in singles in stead of having to wait for a group buy. Weight should be around 3kg.
Kind regards,
Serge