i have a 02 f350 7.3. i have a 4 in exhaust and a cortex. dosent seemed like the cortex added much power. i uped the fuel pressure. i know that you could take a resistor off the map to ground as a boost fooler. it worked great on my 00 but i sold it so i cant look at it and see what resistor i need. also i have a stock air intake. i rember hearing something about a diy deal useing a round paper filter from napa. but dont know what one etc....... any other cheap power adders? i dont need to much more but it would be nice it had more than it does now. thanks!!