I used to own one of these vehicles (1994-1997). I bought it at 77K and sold it at 208K. Absolutely the best car I have ever owned. Only thing I replaced other than maintenance items was the glow plug regulator. Fast and peppy and very economical mpg. I had a 1985 300SD before that car and the 300D was head and shoulders more refined than that one.Now I have a 140 diesel....and I love the car but the maintenance/repairs have been a nightmare.
If the 300D has been taken care of it should be an excellent car