Since you have so much invested <img src="/forums/images/graemlins/lol.gif" alt="" /> Here's my personal list of upgrades to recommend, in the general order I would try also.
(1) Air locker/disc brake Montero rear end. Search on it.
(2)Front brakes off later model Montero. Covered here by a lot of people. With bigger tires, these bigger brakes will make it a lot easier too handle.
(3)Front LSD from a Starion/Conquest and some plh manual hubs. If that isn't possible, Lincoln Locker and definitely some manual hubs. With the tires and wheels you have and these changes, you'll be embarrassing you're lightly modded but bigger tired heep buddies.
(4) BL and tires and wheels.
With just this stuff, with Mitsubishi's overkill on dependability you will be rolling by all the jeeper people. I know I do.