Labor runs $250-500, dealer will be 2x or more. It's hard to do without a lift.
You can pick up a used T-Case for around $1500 on ebay. New from dealer is probably now around $3500-4000.
Jack's does some work on the X case, don't know if others have offered real service yet. Waiting for an upgrade to the ring and pinion might be a good idea if you can wait a year or two, they will eventually make some kind of strengthened parts for the X. There are a few options for the front diff including the Quaife ATB and a few plate clutch LSD's like the Cusco.
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