Re: Air filters these are some "real world" tests I've read about from BITOG:

Air filter filtration test
http://bobistheoilguy.com/cms/index....d=66&Itemid=76

Air filter flow test
http://bobistheoilguy.com/cms/index....d=61&Itemid=70

No free lunch I guess, these "real world" tests seem to support common sense, that more flow = less filtration and vise versa.