I'm using the STI organic clutch disc(for a 5MT) and an STI type RA pressure plate (from a 5MT) and I had alot of shudder and slip also before it broke in. Now it's alot smoother.. grp. N tranny/engine mounts also helped considerably.
You are refering to using a 6MT pressure plate and clutch in a 5MT? I know some people have been doing this lately