i should clarify, it will flow more, and filter less, for MAYBE a month... after that, it filters worse, AND flows less for a period of time, and then it filters better than paper, but flows maybe 1/2...
honestly, if you want performance, and not worried about filter quality, take it right out... you will actually have better results with no filter, as the oil from the filter won't get on things, and make everything sticky for dust to stick to...
personally, i stick with the paper filters... if it's good enough for ford to use from the factory, it's good enough for me... and as for actual hp gains, i've yet to see an actual independent study be done on it, and post positive results...
the reason for these issues? simple! there has been several people who have cut open a K&N filter, and a paper filter for the same car, the paper filter has roughly double the filter media, when stretched out, this gives double the surface area to get dirty, and double the surface area to allow air to flow though... don't you think that if they were that much better, ford would put them on atleast one model from the factory, be it a GT500, boss, mach 1, gt, shelby, svt... but to the best of my knowledge, they ALL come stock with paper filters, not even variants of the K&N (oilbath) style...