The 6 piston caliper suppose to disipate heat much faster than fewer piston and crack like this should not happen at all. It must be the material that they used is not strong enough to withstand the heat generated by the racing pad, but regardless, it should not crack like this at all.
7/08 135 Coupe, Crimson Red, 6 SP, Sport, Taupe Lette/Aluminum. Performance Mods: JB4 on Map 5, BMS DP Fix V3, Injen polished intake, AR Catless DP, Maddad resonated mid-pipes, aFe exhaust polished tips, ST Suspension Coil Over and Hotchkis front sway bar. Others: BMS OCC, BT Scanner, Mud Flap. Next Mods: AA Front Strut Brace.