May 25, 201313 yr supposed benefit is slightly freer revving due to less weight - I've been running a JWT flywheel for about 5 years with no problems, mated to an RPS street sport clutch. I couldn't tell if it made any immediate difference because I'd had a lightweight crank pulley and a boost leak fixed at the same time! I'm not sure how well they can cope with proper racing clutches - I'm sure someone else will be able to provide more info
go for it or waste of money ? :) and the best place to get it ... thanks