As far as off road ability, little else will give you more bang for the buck than a locker. Your vehicle is normally an "open diff" which means you transfer the power to the wheel with the least traction. By use of a locker power is evenly split between both wheels. There are several kinds of lockers. We use a lot of positive locking that replace the spider gear (such as the Powertrax and LockRight). These units are extremely easy to install, require no R&P, easy to setup and work great.
