I purchased a K&N when I first bought my truck back in 98. I promptly sent it back after holding it up to the light and being able to see through it. I'm sorry but if you can see through it, it's filtering abilities are questionable. Add to that a bunch of reports of dirt in the air intakes of trucks. To back this up, have you EVER seen K&N brag or advertise about their FILTERING abilities? I haven't... it's all about their airflow. I've often wondering how many air filters I could sell by advertising that they were the world's highest air flow filters and, here's the best part, they're invisible. I wonder how many empty plastic bags I could send people (complete with installation instructions of course). Here's another thought about the "over-oiling" issue... just a thought mind you. I wonder if all of their filters are passing stuff and the only people that see it are the ones who over oil their filters. If you don't over oil it, oil doesn't coat out on the intake and there's nothing to catch the particulate junk. Again, just a thought.
Anyhow, after all that... check my sig. When I started bombing I got one just for the performance increase but I realize that it's probably at the cost of better filtration. I accept the trade off...