I had an RNS510 in the Mk5 r32 which I bought and VW installed, no issues with it. Should have kept it when I sold the car.
I asked VW to price one and they have said that they can't supply one to retrofit as they will need to order other bits for it. So they have offered up an RMT 400N. Anyone have one of those installed in their Mk5? Any photo's? Seems like a good unit but I'm not sure I like the buttons at the top of the unit instead of the bottom.