What kind of miles and time are you putting on those filters. There was a recent thorough test on filters that have concluded the same thing I have concluded, synthetic fiber filters are the way to go. If you are using Wix XP I would stay there before changing to a none synthetic filter. Other synthetics are Royal Purple, Amsoil, Napa Platinum, Purolator Synthetic. I've cut open many paper filters, at 3 months they are toast. The synthetic ones are pliable, within two weeks I will be cutting open my latest Royal Purple Filter at the 14 month mark to see how it performed, I would have never even considered running paper this long. I probably shouldn't have run synthetic this long either, but we just bought some acreage and I have been hella busy.