Try a search on this topic, it's been discussed in detail many times before.
Briefly ... the 99-up V6 or GT Mustang 2-piston calipers and brackets will bolt right on the 93-up Bird / Cougar spindles, and work with stock rotors. The 94-up Cobra calipers and brackets will also bolt on, but then you also need 13" rotors. 94-98 V6 / GT calipers are the same as 93-97 Bird / Cougar pieces.