Here's one for you from an independent with no affiliation to any manufacturer. I also have first hand knowledge of K&N having personally used a factory oiled filter and seeing the trail of oil and dirt it let in. Yes, fine dirt will combine with the filter oil and engine vacuum will suck it through regardless of your skepticism . I do agree with you however that your first hand knowledge isn't really valuable. It's much too small a sample size. If you're happy with them, continue to use them. I could never in good conscience recommend them and steer people away from them whenever possible.
http://www.gmtruckcentral.com/articl...ter-study.html