the only thing I didn't like about the 4 shoe is when I burn shoes and don't have spares I have to wait.....and same for springs.....when you have over gearing issues the 4 shoes tend to melt much faster do to the smaller mass/shoe...they heat up and just turn to liquid......and the mugen shoe trick does work better but it's just a PITA to cut em...and you will screw up a lot doing them......but it does engage much better than the 3 shoe setup I ran for a while.....you should try tuning your clutch w/ shoe and spring combinations before buying a new setup though