Power steering gearbox puking

My 300s power steering works well but squeaks and is a bit sluggish occasionally when first warming up. I check the levels on fluid routinely and noticed it was low last week. I filled it to the fill when cool line and thought nothing of it.

Today I started her up and there was a steady drip on the drivers side on the concrete. Further investigation found it to power steering fluid coming from where the steering shaft attaches to the gear box (see pic). I looked at the FSM to see if this is a replace entire gearbox job ( seems to be) or a break it down and replace the seals job. (There are a sh$t load of small parts in there according to the FSM). Any idea on cost of a new power steering gear box from those who have done it and any particular problems to try to avoid? As always thanks in advance.
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Author: pmschmitt