I think the earlier AUE engines don't need their chains changing, the BDE ones (post 2001) need changing at 100K. Haldex 4wd should be serviced every 20k, with filter at 40K. Radiator fans have a fault where the smaller one doesn't constantly spin, easy fix with a resistor.
Bora and golf are pretty much the same running gear and engine wise, except things like the exhaust is longer...
Plus all the usual MK4 things, rust etc.