I've had the AA Performance Green Filter in my car since last summer. As mentioned before they are top quality, perfect fit and improves airflow over factory. You can get the Green Filter cleaning kits cheaper online without having to go through AA. I'd say they are a comparable alternative to the K&N filters.
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2008 E92 M3, Alpine White & Black Extended Leather, 6MT with all options. Slightly Moded: BMW M Performance Exhaust, Rear LCI Taillight Retrofit, Angel iBrights, MGP Aluminum Caliper Covers, H&R Springs, H&R Spacers (15mm F and 12.5mm R) with +1 tires, Aluminum Pedals, Black Gloss Front and Hood Grills, Alpine White Side Grills and front reflectors, Active Autowerke Green Performance Filter.