I agree....stock is great, but not the best. I am one of the fools that fell for the oiled filters and nearly paid the price. Only problem is when I attempted to go back to factory I was a fool again and dumped the plastic box which is about $350. I went on a search and found a Donaldson system that even says Ford Powerstroke on it, come to find out it was sold by Ford for quite a long period. It is a true cold intake filter and designed for this engine........very impressive and filters about 300% better than stock and it ought to, the filters are $65 each but last a very long time. It comes with a box that is built for the area it sets in and a tube that brings in cold air from the front as did the original...........this is the same filter that protects military engines in the desert environments. I think this is about the best you can get for the Powerstroke engines.