High frequency sport sound right after acceleration. Not too loud while cruising. Quiet at idling. Exhaust system that links with drivers’ mind. There should be a performance sound quality whether idling in the morning or at night, daily driving, or during spirited driving. HKS utilizes the latest sound control technology to develop exhaust systems that are tuned to the driver’s desire. An unprecedented exhilarating sporty sound from the SSM begins the moment the accelerator is pressed.