Fitting a K&N filter to a Diesel 1 series (best way) | Baby BMW Forum
Amazon.com: K&N Engine Air Filter: Increase Power & Acceleration, Washable, Premium, Replacement Car Air Filter: Compatible with 2006-2014 BMW (128i, 328i, 325i, 328i xDrive, 330i, 130i, 328xi), 33-2332 : Automotive
Stock air filter or K&N Cold Air Intake? | BimmerFest BMW Forum