These kits feature a non-SAC mechanism pressure plate, which , deviating from the original design, provides a lighter rotating assembly, higher rpm capability and greater clamp load levels. Required for the install is a billet rebuildable flywheel that features a lightweight, low MOI design and infinite rebuildability.
You may also be interested in the SPEC BMW Clutch (335i & 335d).
Note: This SPEC designed flywheel cannot be fitted to an OEM design flywheel.
Steel or Aluminium?
The aluminium produced one of the highest wheel hp gains we have ever seen, 17 whp (on an otherwise unmodified car).
The steel produced around 10 whp. The steel dampens more of the gear resonance and, thus, is quieter at idle with the pedal out than the aluminium.