A set of 404 portals will run you about $1500 another $250 for a pinion conversion from there it's the same ol SAS and since they come geared for 37"+ size tires with lockers you don't need to upgrade those parts.

The least expensive SAS is a Wagoneer Dana 44 setup, these can be done on the really cheap.



The cheapest most capable way to build is keeping the IFS, honestly you can make your truck more capable on stock axles for less money than probably any other vehicle. Flip through the builds here and get some ideas. The Montero guys here have collectively done some of the toughest trails on stock axles so take off the sway bar add lockers, gears, 35's and meet us for the Sierra Nevada Challenge in September.