Fidanza is the cheapest I’m sure. Aluminium flywheel is lighter reciprocating mass so les hp wasted to get flywheel sturning. Mostly the engine response is noticeably quicker. When changing clutches you buy a “friction plate” instead of getting the flywheel ground.
Previous owner of my Roe Sapphire GTS upgraded to an aluminum flywheel and sait it was faster through the AutoX. He drag raced the car a lot at the V10 nationals. He went back to a steel flywheels so he had a little extra “oomph” getting off the line at the drags.
My 1500whp TT GTS has a Fidanza aluminium flywheel. I have a Fieanza flywheel in one of my Stealth TTs. I have 2 aluminium flywheels on the shelf in my workshop, a Macleod red anodized with friction plates and a Fidanza. Fidenza-Alum-Flywheel-5.jpg