I have a 2000 F-250 V-10 automatic with a 5 1/2" lift and a 28 foot toy hauler. My truck pulls it just fine. I have put on a bigger trany pan and trany cooler with a fan. Once I put the lift on I dropped about 2mpg and some horsepower. I have not chipped my gas engine but have looked at super chargers. My friend has a 6" pro comp lift and has chipped it, he pulled my toy hauler last week for the first time. He was in stage 2 of his program and it did just fine. He got about 12mpg highway. He doesn't have any gauges like me so we are not sure how hot things were getting. Any more questions let me know.
rtcash@bmi.net