I have an 06 xlt ext cab long bed with HD package. I just installed a BDS 8" lift and am putting 38x13.5x18 toyo m/t's on it. I currently have 4:10 gears and would like to go to 5:13 gears to get as much power as I can. I'm not worried about gas mileage but I herd that I couldn't run 5:13 gears with the ford IFS. Any help would be great!