I have the K&N Cold Air Intake and Down Tube installed on my 04. 5 CTD auto quad shorty. Also have the BD Power Pup set on performance for around town city driving. Man does it pull like a mother... . Anyway I have looked for others that have the K&N Intake and I don't see many. As a matter of fact I have yet to find anyone on here with it. I got it from a well known Diesel expert who has a great shop in Miami and paid nothing for the setup I have, no complaints about that!! My fuel mileage is OK but not as good as I had hoped. On stock setting at 2k RPM/70mph pulling my 10K fifth wheel I get about 12. 5 mpg which is great as far as I am concerned. On tow mode it drops to 11. 2 at 70mph. And stock empty around town it is about 15. 5 city and 19/21 highway at 70mph. I have had this setup for a few months now and the truck has 30,000 miles on it and I keep reading people getting better. Are they BSing or is it a fact. Is the K&N a good intake? I have read pro's and con's on other sites but not much here as I said. Past experience's with K&N have been great on other vehicles I own but not to sure about this one on the CTD. Any help would be great.