MWR air filters for the Kawasaki Ninja 400 are designed to maximize airflow by eliminating moldings, thus maximizing the amount of surface area available to move air into the engine. MWR has two types of filters, the Performance version and the Race version. Tested on similar machines with appropriate changes to the mapping, the Race filter has shown horsepower gains of up to 7%. Suggested retail for either version is $87.95, from BellissiMoto. For more information, contact BellissiMoto, Dept. RW, 6175 S. Pecos Rd., Las Vegas, NV 89120, (702) 901-4028, www.bellissimoto.com.