do u gain any hp from a high flow air filter except not having to replace it i want real proof hp before and after with air filter installed http://www.gixxer.com/forums/images/graemlins/piss.gif

not much..

There is a little improvement with a performance filter but also remember that the more free flowing a filter is the more dirt it lets in also.

I've got the BMC Race filter on both my 1K's. Just clean them a couple of times a year and don't worry about it. They are actually getting really good at making the OEM filters flow really good. As good as the stock replacement K&N's or BMC Street filters. So unless you want the race filter for some (Small) performance gains and want more then just not having to buy one because they are reusable, then I would keep the OEM in it...