I have some experience with this engine . Not a bad design but this design takes much care keep running . It is underpoweredand designed to run 55 mph and not to really designed to be pushed up hills . Its' main design was improved mpgs over their gas powered counterpart , not by any means performance .
All diesel of the mid 80s were built to meet yearly increases in CAFE standards . Those increases were dropped in 1987 model year and all diesels were withdrawn that year from the US market .
If you do push the vehicle too hard it will burn the turbo & the engine up . This is a vehicle designed for a different time when the max speed limit was 55 mph . In the era of 52 hp non-turbodiesel Rabbits & Jettas with 0 to 60 mph times in the 15 to 20 sec. range .
Good luck , pm me if you have any specific questions .