Oh man. Skip the Center Force and the Clutch Masters.
Do a search on them on the SE-R Mailing List archives. Also search on:
Clutchbastards
Clutch Bastards
Clutchmasterbaters
Trust me, you don't want one.
The ACT is an excellent clutch. It is one of only two aftermarket clutches I would use. It has a slightly higher effort than stock.
I use the JWT clutch in both my G20 with SR20DET and my SE-R that had the same engine as Mike Kojima's in SCC's Project SE-R. The JWT clutch has equivelent clamping force as the ACT and it actually has a
lighter effort than stock. Honest. It's unbelievable.
Stick with either OEM, JWT, or ACT.