I'm sure everyone has seen one or two reviews for filters. well here's two more
http://www.mkiv.com/techarticles/filters_test/2/
Apexi FTW - I haven't heard of Apexi Power myself.
http://www.bobistheoilguy.com/airfilter/airtest2.htm (flow test only, K&N FTW)
Which filter elements do people prefer ?
Any links to Great filter studies?