If you are going to swap from dirt to SM, I would suggest keeping the SM caliper (w relocater), brakeline and upgraded master cylinder togehter as a unit and swap the whole thing. Then have the whole stock unit to swap on for dirt. It is easier to swap that than swap disks. That way you use the stock setup for dirt and the high braking power setup for SM. Also the large rotors tend to get bent in the dirt. Cam.