The Cup is supposedly 3mm lower than the MK2 172. I remember reading something about it being the change in some angle or other that makes the car lower, not the springs.
Ive got a set of MK2 springs with only about 2000 miles wear on them, and am thinking of putting them on. Drove abbs172s Cup and the ride was softer while not rolling too much. The Spax springs ive got on make it handle really well, but the roads round here are so broken up its making the interior rattle worse than ever.
If the MK2 springs are the same as the Cup, Ill chuck em on, otherwise Ill buy some off a Cup owner whos changed their suspension.