For those of us with the 2nd gens who would like to get air lockers but aren't really sure if we want to shell out a whole lot of money to have a shop install them. Check out East Coast Gear Supply and give them a call. The sell assembled 3rd members for the front and rear diffs with gearing of your choice. They offer free ground shipping for orders over $500, which is a given with this upgrade. All they request is you mail them your current 3rd members back to them. They include a shipping label with the new ones so all you have to do is put the used ones in the new ones box and drop them off at the post office.
I just bought fully assembled front and rear air locker diffs with 4.56 gears and the compressor kit for just north of $3200. A local shop quoted me almost $5k for a air locker install and re-gear in my stock diffs. this is a pretty good deal IMHO and worth checking out. Not sure if other gear shops offer fully assembled 3rd members.