Hi Simon
I have an 08 R32 will full height MFD, the car originally came with the RCD300.
The previous owner retrofitted an RNS-510 into the car with the iPod MDI kit and sat antenna, he had to take the car to VW for them to code the unit to work with the MDF and wheel controls.
I now have a unit which integrates properly with MDF for navigation,etc.
Recently the maps were updated for the RNS510 to V5, they now include speed limit display, in addition I have loaded up a set of custom POI's (from another member on this forum) and the unit gives me a visual indication of speed and red light cameras on the map. I find this useful as it is free and easy for me to use, I have a Garmin 3790T which I used to use prior to getting this car, but it never told me about cameras and I didnt want to mess around loading custom POI's. The custom POI's in the RNS510 can even show on the map when im near BP service stations and a heap of other places like fast food places,etc...

The RNS510 is a good factory match for an R32 and I have been pretty happy with what I have been able to achieve with it.