The VTC (Variable Timing Control) is designed to work with the standard pistons and camshafts if used with either high lift camshafts and/or high compression pistons, the standard VTC and standard ECU settings may cause the valves to come close or in some cases touch the piston (TODA's A3 cam and larger require the clearance to be checked). Retraining the VTC system for the advancing of any high light cam bring benefits to low end power and low speed drivability.