How many CV axles have you broken? Are you still able to get an alignment or is your suspension so bent than they can't do it anymore? How many idler arms have you destroyed?
What darren and I are trying to tell you is you don't even have 1 locker yet, let alone 2, so you don't know the limits of your truck. You may think you do, but based on your past questions, I don't think you do.
Do you care if you flop your truck on its side or rolling it? Do you care about mashing your doors into some boulders? Can you weld well enough to trust your life on it? With IFS, some armor, and some lockers, you can run the rubicon. Are you going to be doing trails as hard as or harder than the rubicon?
When you're ready for an SAS, you'll know it. You won't have to ask.
In the mean time, you can search around on
www.pirate4x4.com for sas questions. I warn you, do NOT post any questions. SEARCH first, or you will be flamed so bad you'll be turned off of 4wheeling forever. Be sure to look through the FAQ in the toyota section.
I'm trying to guide you, but you have to do the leg work. Don't expect to learn everything in a couple days, it would take even me months to do the proper research to do a SAS and I already have an idea of what's involved.