lol...K&N actually let's more stuff through. Why do you think they make and recommend using foam "PreCharger Filter Wraps" for off-road and "dusty conditions" over their filters? It's a trade-off. Increased air flow at the expense of better filtration. It shows up in the oil analysis as increased levels of silicon. If you don't mind the extra wear, then it's an option for a bit more performance. GM issued a TSB concerning reusable aftermarket filters that use oil...seems the oil migrates to the various sensors and gums them up causing various engine management problems...honoring the warranty could come into question if a fouled/gummed up sensor needs to be replaced. Count the number of folds and the height of the folds...and you can see you have even less total area for filtration than a paper filter. That usually translates into more frequent cleaning since the K&N filter will plug up or become more restrictive faster. Of course it all depends on where you live and the the local environmental conditions one faces in their daily drive. Another thing that bothers me about the comparison tests is that the K&N is usually "pre-dirtied" with their own "dirt" to achieve the 97% filtration mark. What's up with that?

One has to decide whether or they can feel the 2 hp increase through their "butt dyno". The cost comes out the same if you buy paper filters or clean and reuse K&N type filters (max 25 times). The cleaning and oiling kit costs about $20.00.

WIX now makes cone paper filters in various sizes and shapes for those that have a "cold air" or FIPK systems installed. Obviously there is a demand and a market for it.