Interesting feature of RNS-E 2010+ in D2 -- road speed display. Road maps DVD has information about road speed of each major road. It is used to calculate travel time, etc. RNS-E 2010+ displays maximum road speed in the right lower corner of the screen (see 30 MPH sign while car is driving on Nine Mile Ride road). When you pass speed limit sign the sign in the corner of the screen changes accordingly. If you turn to a small slip road or unadopted road the speed sign disappears. As soon as you're back on main road the sign appears immediately.
Road speed limit feature only works with Audi CAN Gateway installed between Drivetrian CAN, Infotainment CAN and Convenience CAN. This allows information from ABS sensors from Drivedrain CAN into Infotainment CAN where RNS-E can read it. I believe this is needed for more accurate speed measurment.
P.S. The smaller speed signs on the map itself are locations of speed cameras. Black background -- mobile cameras and white background -- fixed cameras. This is done with navpoint.co.uk software that injects speed camera data into a separate POI layer of DVD. Subscription to popular speed camera database is needed. Navpoint will work with pre-2010 models of RNS-E