I'm new to this forum, and fairly new to diesels. I got a '02 F250 with 270k miles 2 months ago. Runs good when empty and sounds/feels solid, but when pulling my 3ton job trailer from Dallas to Memphis it just couldn't keep me up to speed (slowing to 45/50 in the rolling hills). I have to pull 600 miles in 2 weeks, so I don't have much time for research. Can ya'll help me narrow my performance options so I can make a good decision I a short time? I am not interested in hot rodding. I'm just a contractor who travels a lot, i.e. work truck. The truck already has a 4" exhaust and will be getting a air box this week. Any uncomplicated input will be MUCH appreciated.