I have a 6 inch rough country on 37s with 20 inch rims, before i put my body lift on as well, i had a slight rub on the front bumper, so i had to do minimal shaving. i have no issues any more. i also have my bilsteins at 0 because i like the look of the rake, but im sure you would be good. i also have the 3.92 gears. I want to raise them to 4.56, but they run very solid with the bigger tires. your mpg will take a big hit, but i didnt really buy a truck for mpg, so thats the way i look at it. by far best truck i have owned and is still running strong. you will enjoy it.