So you want an Golf III, two things the 1.8ltr engine is much better than the 2.0ltr. Mine was '93 I just crashed it band bought a 2000 tdi last week.
1) parts are easy to find and pretty cheap.
2) very important follow mantence sch. even if yoo think everything is ok. do as the book says, delays cost a lot of $.
3) insuance $1500/yr Gold are rather 39/100 for theift so you pay for the theift risk.
4) My TDI $1920 2d or $1984 4D TD Insurance.
5) repairs pretty low tech for the oil change filters, brakes, muffler but don't touch the plugs get that done at a specialist.
6)I'll tell you next year I just got my TDI.
7) I'm 6 2' it no problem.