Do a search on what to look for in a 300TD. Ignore the parts about the engine. There are things to check specific to the M110 engine. You can try searching on that but I haven't seen much 'what to check' for M110s.

Since the 280TE was not officially imported to the US, be suspicious of mileage particularly if the speedo is of the US-spec mph/kph variety. Who knows how many kms were logged on the original speedo.

Sixto
95 S420
87 300SDL