The 5th gen 4Runner and GX460 (150 series platform) has proved to be extremely popular amongst overlanders, weekend adventurers, and wheelers alike. While they are extremely capable out of the box, the 4Runners only had rear lockers on some models and the GX460's had no lockers at all. While the ATRAC does a great job of getting you in and out of some tricky situations, sometimes the computer needs to sit there and figure out what's going on and while it does you will lose some momentum. Additionally, with big tires, armor, and all your camping/adventure gear, the truck will be working extra hard. Re-gearing the differentials would help compensate for the additional tire diameter