Bad news, dude. My local, reputable, MB-specialist indie garage finds my steering box in need of replacement--not urgently, but before any of several other things I ought to have done by next winter (my MB's a 560SL, warm-weather only in Michigan, meaning April/May through October or so). In round numbers, the box is $900 and there's another $250 in labor. If you do have it done, have them check the ball joints as well; I've got one that's worn enough to be eligible for replacement, for another $225 (parts and labor together).
They're great cars and they'll last forever--but not without work along the way!
'97 SL500, 40th anniversary edition
'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)
SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)