mugen filters work fine, make good power etc. and they seem to be the only ones that fit a sedan properly. difference being, if your running a $500 engine, why would you clean a foam filter? all it does is pushes the garbage farther into the filter. Replace the filter element rather than cleaning. I have friends that wear by cleaning filters and I tear down their engines and they are all pissed off.. buy more filters and replace them hourly or more depending on how dirty/ dusty your track is.