I have an Airaid oiled filter but was never completely sold on them. They really can be a PITA to clean and re-oil. The first time I cleaned a K&N filter it took almost 3 days to dry, so I needed an extra filter to put in the car. Then when I re-oiled it, I used a bunch too much and had oil dripping out of the filter, so when re-oil the filter it is best to use just a touch of oil, wait at least 20 minutes to see if the oil has completely soaked through the gauze, and it not, a touch more and again wait to make sure you haven't overoiled it and clean all the oil off the non-gauze areas of the filter. With the Airaid filter, I have found it stays much cleaner running it with the pre-filter, but again I'm sure the pre-filter adds some restriction. I know when it's time to replace the filter I'm getting the Airaid dry filter.