with the 4 pot set up, I suspect u need to step more for the brake to bite... Cos more fluid needs to be displaced to push the 4 pots.. That's what related to me by a buddy of mine running a 4 pot Nissan brakes... next up is the E38 dual diaphram servo.. Actually, the E32/38 servo conversion is one of the common upgrade here to increase brake feel but it locks up the wheels easier too, especially in the wet..