Coilover kit - BC Racing - RM Series - Corolla 1.8 T Sport ZZE123RM Series BC Coilover kit for Corolla 1. 8 T Sport ZZE123 The RM coilovers offer the majority of the features of the BR series but with the additional benefit of the inverted damper unit to reduce unsprung weight and further improve handling. 30 position damping adjustment adjusts both bump and rebound together. The RM series coilovers use a large 42mm diameter inverted damper to maximise oil capacity and reduce oil temperature and viscosity change.