We have had no trouble getting parts for my sons 1985 300D NA (non turbo) belts glow plugs ect have been the same as the older 1981 300d until the transmission went out then it was pay close to $1700 for the rebuilt transmission not including installation there not available in the junk yard. We finally saved the money for that and I said BS I went to pick-N-pull pulled a 1982 turbo transmission and with some creative adapters, it has been in the car over a year now. We bought the 1985 300D EURO after my sons 1982 300d was rear ended and the EURO feels light and tiny in comparison the EURO is no where near as sure footed in corners as the 1982 USA car was. Basically the 1985 EURO seems to be cheaply built compared to the 1982 USA version although the interior of the EURO car is definitely of a higher quality than the USA car.
My 2 cents
Dave S