The air lines to operate the ARB can be problematic, plus you have to run an air compressor to operate the
locker.
If you want a selectable
locker, check out the cable activated OX locker, or the electricly activated E-locker that just came out.
A lunchbox type locker should work just fine for you, EZlocker or Lockright.
Since money is no object, you may want to upgrade the entire rear axle. The Ford 8.8 can be found with the correct gearing and disc brakes AND limited slip differential out of '95 and later Explorers, Mountaineers, Navajos, etc. It has the correct lug pattern is and is only slightly narrower than a stock D35, but a LOT stronger. We've twisted D35 axle shafts on the last two club trail rides we were on, and both those jeepers are upgrading to stronger axles.
Also check out the Super35 kit, comes with heavier, stronger axleshafts and either an OX locker or Detroit locker.
The possibilities, and opinions, are endless
[addsig]