Another thought is that you could check around in the "gasp" junkyards and see if you can find one of these. On older cars when searching for unique parts like transmissions and steering gear, I have found that if you look carefully, you can often find a low mileage component for a significant fraction of the new or reman cost. Of course if money were no object, I would be driving a new E430. I would think you could find a steering box for this one. As regards reman or used, false economy to go with the used.

Good luck......