I got a pair of front PBR calipers off a 2000 Mustang. I've been meaning to sell 'em, if you're interested PM me. These are two-piston calipers, and you will need to grind off part of your current spindles to get these to fit.
You can also pick up a set of 99-04 spindles to replace your own to avoid any grinding. Be aware that the 99-04 spindles will add a total of 3/4" to your front wheelbase. If you have the 03 Cobra a-arms as well, your wheels will stick out past your fenders.