you can install the complete abs system from a cosworth a equivalent XR model.

imy saph was originally a 2.0 ghia so had disc brakes all round and no abs - i have uprated the front brakes but not changed anything else.

If you want to do the above you will need to change the master cylinder for something like mine as it had discs all round.

Ive got Focus RS brakes on the front and they are great