This kit is configured for dedicated road racing on all 1994 - 2004 Mustangs, or any 1993 and earlier Fox body that has been upgraded with the 1994 - 95 model SN95 spindles. Four piston, nickel finish Quick - Silver FSL4RST calipers, with Thermlock pistons and internal knock - back damping springs, are volume matched for system compatibility with either a factory vacuum power brake booster and master cylinder, or a manual balance bar style pedal with appropriately sized master cylinders. The kit includes two - piece 12.19 diameter Spec 37 alloy GT series directional vane rotors to comply with SCCA American Sedan rules, cross - overs into the NASA pony car categories, or any other sanction racing with 16 or 17 wheels. Unsprung and rotating weight are minimized by mounting the rotors to the OE hubs with forged aluminum hats. Each kit includes high - temp Wilwood race compound pads, machined billet radial mount caliper brackets, stainless steel braided flexlines, and all premium grade hardware.