I used to love K&N. I had one on all of my previous vehicles. (Maxima, NX-2000, Gti)
But now I worry about oil contamination on the mass air flow sensor and poor filtration. The newer cars seem to be more sensitive than the older ones.
I use the factory filter, but the e46 M3 version (13721730946) that is an extra 10mm thick filter instead of a black foam "pre-filter" glued to the bottom of the filter. This filter fits your car.
Last edited by Max_VQ; 05-28-2008 at 12:53 AM.