For street use stock brakes are fine. If you go significantly larger sticker tires you might find a need for improved pads. Big brakes are really only useful on road race track where repeated braking can cause smaller brakes to over heat. I do love the looks of huge brakes.
2010 GTRR in 5.0 Magazine [http://www.mustangandfords.com/featured-vehicles/m5lp-1212-2010-ford-mustang-gt-rr-total-fabrication/viewall.html]
2015 White SC, PP, etc....