Great car, bought a 93 new, then after it was totatled bought another.

I've owned M/B Diesels beginning in 1978, have owned all of the prior and subsequent years turbo diesels. In my opinion the 300d was the best one they ever made, first of all its a modern car, abs, airbags, mine had asr as well. Quiet, reliable, good brakes good handling. Best interior materials, very high level of finish and very durable.

The downside, turbo lag off the line, just fine underway. The old style vacume pumps did not have a basket to catch the many ball bearing that will find their way into the timming chain and sump destroying the engine, if the car has the original pump change it ASAP. The new style has a different bolt pattern on the cover, due a search. I would not change the timnig chain unless there was steach or a suspect oil change service interval.
The engine is controlled by a first generation computer, generally not a problem, however there are many vacume servos controlling inputs to the computer that do cause issues, mainly putting the car in the limp home mode, no boost. The shock tower welds along the firewallwere and issue on some cars, my 93 experinced a clicking sound the result of a bad weld. There is a factory bulliten. Might want to pick up Stu Ritters 124 bible for more info
All in a great car, good luck