Wilton,

It sounds like you fared pretty well if you ask me ....Some of the people with these cars(including myself) have needed
repairs that were in the $9-12K range
I even know of one guy who paid for his own rebuild(MB rebuilt engine was not available years ago when he needed it)to the tune of $8500.00 out of HIS OWM POCKET.He did get a brand new head which is of a totally different design he said
My car has a completely new MB engine(sans the turbo,but all parts from the valve cover down) and the dealer tech told me the there were some major modifications in the new engine versus the old.From the totally redesigned head to suport parts such as the engine mounts and shock.
The regional MB rep claimed no foul on MB's part with this engine.Because I had a heated conversation with him as to how this could have happened The problem,he said, was caused by lack of maintenance and bad fuel.....but two things are curious here...1.The immediate next day availablity of a complete MB engine for a car that was a very low volumme seller and 2.The myriad of design changes of the new engine versus the old...
I live in Columbus Ohio where there are probably no more than 3-4 W140 diesels in town and incidently there was another 1992 300SD that was also having the engine replaved at the same time as mine. That owner also paid totally out of his pocket(but I was told the dealer did the job at cost because he was a longtime customer)

My repair bill by thy way would have been $10,500
My work was done at Crown Mercedes in Columbus Ohio which I will say I am very satisfied with their service. My car has made them scratch their heads a few times..but they have seemed to have gotten it right

Warren
1992 300SD 113K
Columbus Ohio
turner@greif.com