Coilover kit - BC Racing - External Reservoir - ER Series - Celica GT4 ST205 (Welding required)Celica GT4 ST205 BC Racing ER Coilover Suspension kit ER Series with External Reservoir BC Racings premium flagship coilovers are the external reservoir ER Series with separate compression and rebound damping adjustment. The ER Series coilovers bring with them the high quality and unique features seen on the BR and RM type but have the additional benefit of external reservoirs and the ability to allow the end user to individually adjust and set