HKS Wastegate Actuator Kit replaces the stock actuator for better boost response. Old actuators diaphragm usually wears out, causing inconsistent boost and spikes. Replacing it with a new actuator will help alleviate these issues. Also, the HKS Actuator kit has a unique feature where users can adjust the length of the actuator rod to provide better boost control up to 1 bar of boost manually. It is always a good idea to upgrade the stock actuator if you want to boost beyond 14psi. Boost range higher than 1.2bar can be achieved with the aide of an aftermarket boost controller to direct signals to the wastegate actuator for higher boost pattern. Adjustment of the rod for manual boost control should be done carefully with a couple of turns at a time.