Somebody told me I should put in a K&N air filter. I've got one in my 01 Bullitt so I thought , what the heck. $55.00. Now I started bringing my truck to a guy who is a Ford diesel mechanic and has a really built 7.3 and he says get rid of the K&N. He says something about the air flow and the turbo and he feels its no good for my motor. So, Should I get rid of it? He seems to be right a lot of other stuff.