I fitted a lightened flywheel to replace my already lighted SPS flywheel. It gave me more engine braking and definitely needs a bit more revs when moving off, I also found the engine didn't want to idle until it was fully up to temperature.
As for the screeching clutch, I have the Bicci Slipper that worked great, and then I fitted a set of carbon plates. It now sounds like a slipping fan belt every time I take off. I found I had to learn a new riding technique, let the clutch out fully before gunning it, and don't use the clutch when pulling up the front.
