When i changed to Cossie Calipers and disks all round on my XR2i, the pedal went crap, the car would stop but not like it should, i changed the master cylinder to a MK5 Escort Item, and the braking was transformed, everyone that has driven it comments about the brakes.
I bet ya pedal is spongy and the brakes only start to bite when the pedal is 3/4 the way down?