I'm going to defend K&N a little bit here from the typical bashing they often recieve on forums. Why don't you put a secondary filter behind a paper filter or the OEM filter and look at the copious amount of dirt it collects. Dirt gets past any filter. If you don't believe me check out this link. http://www.bobistheoilguy.com/airfilter/airtest3.htm

Yes, K&N filters let in slightly more dirt than an OEM; I should say very, very slightly. It won't make any diference to the oil or the motor. Oil is designed to deal with a certain amount of dirt, and using a K&N filter is not going to bring the oil over the dirt-threshold point.

Just look at the secondary filter in the tests with a paper filter; it's filthy with dirt. Just think about all the dirt that is getting into your engine with your oem filter. Surely your engine can't survive with all that dirt grinding around in the engine can it? Tired of K&N bashing...