Maybe a good combo would be KN prefilter wrap with an open element paper filter? lol. Seriously, one of the above poster linked a comparison to air filter tests done by an average guy, and that answered my questions once and for all. I used to be a staunch believer in the oiled filters. They do tend to leak a lot of stuff through. You can always blow (with moderate low flow) air from the inside to clean out paper filters to give longer service as well. Here in Nebraska, it is windy and dusty all the time, and it was just a major chore to try and service the pre-oiled type. Maybe if you had 2 of them, one ready to go wrapped in plastic, and when you got ready to clean your other one, just slap it on. and switch back and forth, but still use the prefilter wrap. The air filter on a car is the only thing that works better the dirtier it gets. Until it stops all air flow. Then it is 100% efficient. lol.