There are some OBD2 1.8 8Vs too, my friend has a 1997 1.8 golf.
Body-wise, you should check the whole car, they are cancer on wheels honestly, the classic is the plate-surround that tend to rust quicker than the rest.
Ya mk3 itself
Yeah, I know about the rusting, and that's the first thing I check. Any known issues mechanically/recalls?
Like the coilpacks on the mk4 1.8Ts, or their windows falling out, lulz.
Should be going for the base 1.8L or 2.0L, no VR6 or 1.8T.
Aside from corrosion there really isn't much to go wrong with these cars aside from regular maintenance. The regular bushings, plugs, ignition wiring, gaskets...
If you manage to pick up a clean example (which isn't easy these days) you shouldn't have any issues with corrosion, the ones that had to rust away already have...