SUPER SQV4 RETURN KIT PLUS VMG/VM471008 AF015 FEATURE Installing this product creates unique sharp & high frequency SQV sound. The SQV IV unit is designed to be located beside the engine so the appurtenance of the engine bay is improved. The suction return parts are included (those are necessary to pass the Japanese Automobile Inspection.). Any engine failure such as engine stall was not occurred during the in house testing.