Not sure which 2009 BMW 3-Series Air Filters are right for you? We have over 12273 customer reviews, with an average rating of 4.5, to help you find exactly what you're looking for. Here's what some of our customers have said:
"I have always replaced the stock air filters in all of mycars withthe Kand N filters. I have always noticed slight improvement in performance and a cooler running engine. This time ireplaced the filters in my 2009 C63. And immediately saw a drop of engine temp of about 15'F. In the middle of summer with AC on. As for performance wel the car makes 451hp as is but it definetlyfelt better. Instalation was very easy. Highly reccomend them to everyone witha car or truck." —Charles K from Fairhaven, MA bought a K&N Air Filters for a 2009 BMW 3-Series.