For 31x10.50s, the Aussie locker would be a good choice. Your offroad driving skill will be the determining factor almost all the time as to whether or not you snap an axle. Just carry an extra set of axleshafts for the D35 when your four wheeling and a few tools and gear oil (and something to catch the old gear oil). Normally its the axleshaft that breaks: just hope the differential doesn't get messed up when it does snap. It's an easy job to replace an axleshaft. The important thing is to get out all of the broken axleshaft pieces.

94 YJ, SOA, 2-1/2 Alcans, ARB-front, Detroit-Rear, 4.56:1 gears, Oasis Trailhead compressor, 4:1 Terra Lo, 37x12.50x15 SSR's, 8000 lb Ramsey, & etc.