Mk3 brake for Mk1

Is it possible to fit Mk3 brakes into Mk1? Would that involve any changes in the suspension system?

MK3 brakes are almost the same as MK2. They won't bolt on to the MK1 upright. You can fit a MK2 upright, but this screws up the steering unless you're really low. There's a thread on ClubGTI about it at the moment.