K&N 04-07 Subaru STi K&N Drop-In Air Filter

K&N Replacement High-Flow Air Filters are the original high-flow air filter. Since 1969 K&N Engineering has been designing, manufacturing, and enhancing High-Flow Air Filters for the automotive and motorcycle enthusiast interested in maximizing horsepower and acceleration. K&N also makes filters for thousands of applications, including racing and specialty type air filters and is the only air filter used at the Indianapolis 500 Race.