I would pass and just step up to sn95 or better brakes. If you want to just have slightly better braking then stock then go ahead and buy the 73mm (not worth it in my opinion). If you can't throw down the money for the 5 lug route, then just freshen up the stock system and do it the correct way later. Fresh fluid, new rotors/drums, braided lines and some good shoes/pads will be a hell of an improvement over stock.
Fred