Have you run a search? This a recurring theme and there are countless past threads on what exists. I cannot recount the options in proper detail, so I won't try.

Have you been to the ARB site? They make the only aftermarket locker. Don't know how it fits up to your MS.

Diff gears are also a common topic so seach for that as well.

Welcome... <img src="/forums/images/graemlins/cheers.gif" alt="" />

BTW put you truck info in you profile so it shows up in you posts. It will help others to answer down the road...

Big Truck: 00, 3.5, Endeavor, 5-Spd drive line in hand!
Little Truck: 87, 2.6T I/C, MT, LSDs, Tonneau Top
Her Truck: 03, 3.8, 20th Anniv, 65k
Daughter's: 06 Eclipse, Keeping it Mitsu!
FSMs: MitsubishiLinks.com