You will probably lose a little torque in exchange for quicker revs. I had a OS Giken/Fidanza setup which I ditched for a stock flywheel and ClutchSpecialties. If you plan on keeping the revs high and the motor you are working with revs past 7500 then you could go lightweight.

Also check the ring gear for compatbility with the bendix in your starter. My Fidanza was the wrong one the first time.