Circle track guys like the aluminum because when they lift getting into the corner, the inertia in the flywheel is less and it won't carry the car as deep into the corner. This requires less brake. It can be debated as to whether you should be letting the engine brake the car or not, but that is the justification in some cases. There is also less parasitic loss. With the restricted engines in NASCAR sanctioned events, the lighter the rotating assembly the better. I can confirm that from experience. Now a days though, the aluminum flywheels are mostly illegal in NASCAR weekly racing series competition. They claim safety issue. Must be something to that! I would go forged steel in my opinion. If you really want a more track only setup, use a Tilton Triple disk, it has built in plates and mounts to a flex plate. Great for the track, but do not like starting out. :thumbsup: