ACTIVE AUTOWERKE BMW E9X M3 PERFORMANCE AIR FILTERACTIVE AUTOWERKE BMW E9X M3 PERFORMANCE AIR FILTER The Active Autowerke BMW E9x M3 Performance Air filter was engineered and designed to effectively increase your BMW M3's horsepower while maintaining OEM like fit and quality. The Active Autowerke M3 'Green' Filter features a special reinforced side wall to guarantee perfect fit and no failure like many other aftermarket filters with thin walls. Not only will this system help increase air flow to your