Most performance shops will be able to do it. A differential is a differential.
If you're just doing a differential, its should be around $500. If you're doing ring and gears as well, its going to be more like $800/900 and there is no guarantee that the shop is going to do it right. Once you remove the pinion, that bastard will need to be reshimmed and most performance shops won't have the proper shims readily available.
I ate up my gear ring because I didn't shim my pinion properly. Car ran fine, was just a little loud. After a year, I ended up having to change out the gears anyways for FI.
As long as you don't plan on changing out the gears (aka. removing the pinion), its really not bad. Not sure what you mean by timing? The only thing you need to keep track of is the bearing gaps for the side bearings.
Tools will def help. You will need a pretty decent impact to remove the gear ring though. If you can drop the differential, I can help remove the gears and press the bearings off the LSD. PM if you're interested.
Some resources I found useful:
Pirate4x4.Com - The largest off roading and 4x4 website in the world.
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