The problem I see with K&N and other aftermarket filters is that you get it go wow and then forget about it and never clean it or at least thats what I see. I now have a F250 with a 460 and before I had it, it was a company truck for the family and my cousin put a K&N replacement filter in it. Well 7 years later I go and look at the filter and it is completely black but I do have to say not much dirt passed through. Well I threw it away and got a motorcraft filter. Now I just go get a $15 filter every how many miles rather than finding the time and effort to clean an aftermarket.