skoles- I can't give you a good answer, but some VWs and most Audis (note these cars are corporate cousins) just have very hard clearcoats. My Audis are (according to the Porsche/Audi dealer's paintshop, and this is a good dealer) painted with Spies-Hecker brand paint and it's simpl hard stuff. When I have paintwork done on them, the shop uses S-H paint and the repainted areas are, for practical purposes, as hard as the factory paint. The repainted areas do chip easier though.
If you're gonna get any paintwork done and you want hard paint, I'd consider finding a shop that's familiar with S-H paint, I hear it's not the easiest stuff to work with so you don't want them using it for the first time on *your* car
