Mine was totally killing the bottom end in my Mugen truggy so I took it apart...got a Dremel and lightly ground all the way around the shoes...put them back in and problem went away.
Smoothest grippiest clutch I've ever used. If you get too much low rpm grab then change one carbon set out for the glass set.
I noticed I had two packages of springs...both said they were Hard springs but the packages had different part numbers. You can pretty much tell which are harder by pulling/bending them.
I like how this clutch setup works...it seems to be real easy on the clutch bearings and the clutchbells.