Which is the best air filter?

[motoyen]

I run a K&N based mostly on their marketing claims. However this guy has some interesting results from testing a variety of filters. I recommend this read.

http://www.bolhuijo.com/airflowtest/index.html

[jrez]

That's interesting reading. I wonder how the k&n demo(clear plastic)thingy with the pingpong ball manages to raise the ball further with their filter in use?
I was surprised the amsoil filter did as bad as at it did. I've never used one in my personal vehicle, but I've sold several, with good feedback. Good to read a real independant test though. Makes you wonder about all the rest.

[fastbmw]

Like I always say, BMW parts are always best...

[motoyen]

I remember reading a dyno test where they tested a bunch of different air filters. It was some muscle car mag and they did find that the K&N gave a small HP boost.