I use the 2 shoe with the optional stiffer springs with 2 1/16th holes drilled in each shoe and the light cluthbell.
I use the x12 turbo 5 port and this setup works well on short tracks, gives the RB alot of revs before clutch lok up
Maticore posted in the ntc3 forum some company in Japan I think has the centax clutch available for the car now. Look in the car forum, the addys there.