If they are compatible with the older style wheel hub, you are still looking at a bare minimum around ~$230 for each hub body, ~$420 for the pair of autolocking hub faces, and ~30 for the special bolts to attach the hub faces. I don't know if the auto lockers are compatible with the old-style hub bodies. And that is if the pricing is correct, and usually the price for over seas stuff is a little higher based on my parts adventures with my HZJ-75 build.
So looking at the prospect of a potentially $900 upgrade, I'd get out of the truck and lock the hubs before I went into said muddy field Plus the few discussions I have seen on the auto locking hubs, they are not the best option for reliability.
The electric lockers on the LJ78 are plenty strong. Maybe slightly less then the fully manual ones. But the brushes wear down or get gummed up and then you are stuck. Had it happen a few times. Every time it does I swear up and down I am gonna through the manual ones of my old HJ60 on and be done with the stupid electric ones. Just never get around to it.
I guess I should stick with good ol manuals. I don't like the idea of electric much, I was thinking along the lines of the old warn lock o matics. It sound like none of them are that reliable. I wish there was a good system for it.