I found my car ran best with a steel wheel and some mass. I found revs still dropped fast and never had shift problems. That car made 500hp/500ft lbs on pump/race blend of about 97 oct.. Intake manifold was a restriction at that point and Iwrecked the car b4 doing that piece. I had an alum piece and it chattered a bit with the 5 cyl and a rs2 gearox.
Rod

Check Motorgeek.com and look for a Derrecuda character, he did a GB a while back.. my wheel is 11 pounds and oh so nice.

As fasr as chatter, i do not understand why alumiunum would cause chatter over steel. comming from the mc1's near 30 lb weight, it is a hell of a difference, from quicker response to easier rev matching, and smoother operation up around the higher revs...