I have a 2002 F550 Box Truck with a 16 ft box and large liftgate. It weighs 12,800 lbs empty and usually has 3-6K extra in payload. The truck has 320K miles and new injectors, glow plugs, upgraded donaldson intake but only gets 8.5-9.5 mpg and is pretty slow as you would expect. I don't want to race it but would like better mpg and a little more merging power. Any recommendations on a chip/programmer and exhaust? I want to spend as little as possible and would like to keep the total cost around $1,000. Do I need to special order the exhaust for the added length of the truck? Will the programmer need to account for the larger differential in the F550 over an F350 or are they all the same. I don't want to cause any problems or lessen the life of my motor.