I've done some searching and found that we have to swap our 3rd member with a pre 2000 vitara.
What exactly dose this entail, dose everything match up?
Why do they need to be swapped?
is it the hole axel or just the carrier, i am kinda confused    iv heard the carrier also called the pumpkin and 3rd member interchangeably and also herd the hole Axel Assembly refereed to as the 3rd member.

I do need the 5.12 gears; I'm running 31's  , but the locker is expensive enough now i have to get new axles, probably need to put seals in them and all sorts of Little expenses like fluids, knuckle band-aids, brake fluid, and whatever I brake while I'm in there...

someone tell me its not all that bad  :'( 

ok, it's not that bad 

Find a pair of 5.12 thirds (You do realize, both diffs need to have matching gears).
Get the lockers you desire.
Take them in to a shop that can install the lockers and reset the gears properly (or DIY if you've got the skill and tools to do it)
Now, pull the thirds from the front and rear, and install your new diffs.
Change out the front hubs to manual ones, and plug the 99+ airline that runs to the old third.
Sell off the old thirds (you should be able to get a few bucks for them)

You will probably need:
Some new diff fluid (I think 3 quarts is enough)
Slide Hammer (helpful for removing the rear axle shafts)
Some marking paint to mark the drive shaft orientation.
Normal mechanics tools
An afternoon to do the swap (full day for ARB's with the additional wiring and airlines).

If your careful, you shouldn't need new seals.

Might want to call some of the vendors and see if they can supply the diffs with lockers setup already. When I added a lockrite to the front of my '91, I exchanged my old 4.62 third with a 5.12 he pulled, paid for the locker and a minimal fee for the setup, and plopped it in. (I put a 5.12 + mini-spool in the rear)

How dose the spool handel on the pavement, my rig is a dd. I don't mind chirping tiers.

Well, the spool pretty much sucks on pavement, but that old rig doesn't spend much time on asphalt

I'm looking to get a 2nd gen in the near future and will probably just do an ARB in back and the lockrite up front.

Off-road, it's hard to beat. Pretty much bulletproof and is cheap!

I am running my ARB up front, with a locker in the rear.  That way the steering is much easier and only lock up the front when needed.  The rear locker did buck and kick on slow sharp corners, but that quit happening when I went to the auto transmission.

Well still having trouble, none of the local yards have the axles.found a 97 tracker lsi 150 miles away with 5.12's and no abs.
I'm thinking 5.12's and a locker is worth the sacrifice.
Still not sure if the front housing is steel or aluminum, I need to have steel