There was pics of one done on here a while back.

I put a complete Sapphire front end on a XR4i a few years back - the bumper isn't a straight fit because the bits that hang down from the bumpers are in the wrong place, and you would probably need to drill the front chassis legs to hold the bumper brackets - if you went with the later rubber bungs for the main brackets to push into there is nothing to stop anyone just pulling the bumper off.