Ported Head Pro RWhether you plan to keep your Polaris Pro R naturally aspirated or adding turbocharged performance, this modification adds airflow with oversized valves, and cnc precision porting. Paired with our custom 430 lift cam this kit adds 90hp from stock (stage 5 with our exhaust and ecu tune) STAGE 4 +4 mm intake and +1 exhaust valves Up to 330 hp at the crank Hard Flash is REQUIRED with this kit STAGE 4 (Turbo) +1mm intake and exhaust valves Up to 318hp at