I work at Ford Performance, previously known as SVT, and about 18 years ago while working on the supercharged SVT F150 Lightning program, we performed extensive flow testing on various production and service/aftermarket air filters. As it turned out, our SVT paper panel filter flowed more air and filtered much better than any aftermarket panel or cone filter including the K&N. I never even considered a K&N after that testing for any of my personal cars. The gauze filters rely on the oil to capture the fine particles. If the oil isn't perfectly applied, there is either lower flow or lower flow. Even when correctly prepped, they don't perform that well. YMMV and it's quite possible that we screwed up the testing and they really are the best thing since sliced bread (disclaimer added just in case they find this thread )