just remember how NOT to weld it together
Lincoln Locked diffs are nothing new and far from a "ghetto rigged solution", more a classic fall back in many automotive based scenes. In the front though your gonna pretty much make your front end primarily a trail only thing and a 'i need to get the eff outa this ditch' type thing, not so much a putter around because its a little slippy out in 4h type thing (in my opinion that is, so take it as you will. Of course I also assume AZ don't get winters like say Canada would get so that may not be an issue). manual hubs will be your road savior, i'd suggest a set if your gonna go for it if you like turning I say snag up that spare diff you plan on, weld er up nice and good, keep feedback coming on pros/cons with some good hands on experience instead of some peanut gallery opinions (myself included) and sell off whichever diff you DON'T wanna use
new4x4r said it best, this is Nissan Pathfinder Off Road Association . Making it there safely and intact the fun way is what it's all about!