I am trying to get some info on the after market air filter system, such as the K & N. Has anyone had much luck with these? Do they actually help? Increase mileage? Power? There are many brands out there now, some with the aluminum tube and others with the Poly tubes. Any suggestion or comments in the different types available.

i have the aluminum 77 series intake, i cant really tell the differince, it sounds cool though

Do a search for previous posts. I believe there was one that stated that and after market air filter or intake wouldn't help much at all, some just make you turbo a little louder.

Depends on what kind of truck your running. Please take the time to fill out your sig so that we can better assist you in what you are looking for. In the 6.5, if you open the intake up with whatever and remove the snorkle, it will aid in breathing of the system thus allowing a little more power, sound and mileage. Definitely change out your down pipe as well.

Mark:beerchug: