punto gt brakes fit the same way as tipo brakes onto the same brackets and hub which in turn have similar hub to the coupe, you'll need bigger wheels though and spacers prob as the bremos tend not to fit under many aftermarket wheels.
can i ask what makes you think you need the power of coupe brakes? IMHO you may have more probs with front end lock ups where you could drop a set of gt brakes on with uprated pads and discs.up to you but the calipers alone will most likely cost more than the whole gt set up.depends on the power you are or going to run but if the stop a gt you should be fine