theres a slot on either side of the rail, stick a screwdriver in there and wack it, that will kill the ear that's holding that side of the cup repeat for the other side, when you drop in the new cup make sure the ears pop into those slots, it usually takes a tap to seat them. the bosses kids 98 m3 came with some super duper uuc shifter and imho it's a piece of ****, it's a machined insert that replaces the nice tight fitting cup that basically converts the shifter to a 2002/320i style upper/lower cup and spring set up that sucks ass, the car was undrivable when we got it and all i could do to it barely made it tolerable
stick with the stock set up and sellect your favorite factory shifter for throw reduction
all america wants is cold beer warm cat and a place to take a poop with a door on it