a 1.9D will be the last of the early T4's, they being more typically 1.9TD & 2.4 (normally aspirated ) bot of which are much the same and can be tweaked
then came the 2.5 Tdi etc
VW made them to do a job at a certain pace, and if you can live with that you'll be fine
as with any car of that age service history is everything . looked after the can go on for ever !
19 years of happy motoring in our 1.9TD