Wilwood 140-15138 KIT REAR FFR DPR/MC4 IRS 2015 MUSTANGWilwood 140 15138 KIT REAR FFR DPR MC4 IRS 2015 MUSTANG Dynapro 4 Radial MC4 Rear Axle Kits replace the factory disc brakes and use the MC4 parking brake assembly as a compliment to front big brake upgrades on late model high performance vehicles. High capacity braking from the Dynapro Radial calipers, BP 10 compound pads, and oversized 11. 00" to 12. 88 rotors are matched to the OE master cylinder output, ABS function, and individual vehicle bias