Hi.
I faced this dilemma 2 years ago as used to regularly drive from south wales to plymouth to visit my daughter in uni. Having used a garmin sat nav stuck to the windscreen although very good, i found it too far away to adjust/set up on the go. Coupled with a dodgy volume issue on my concert 2 cd player i decided to go double din upgrade. Was original looking at the Blaupunkt double din touch screen units very nice but expensive. When i installed a single din blaupunkt to my old A2 it had the speed gala function. On further digging it would mean loosing the stereo info on my dis screen. So when a used but good condition rnse mk1 unit became available at a very reasonable price i jumped at it. Yes they are an old stereo but give good voice commands and with coding you can use the satnav directions via the DIS screen and set the stereo on music or radio function. Only downside is no DAB. Currently looking to fit a genuine audi Bluetooth unit to the rnse. To connect my phone, so that might sort the dab issue if i can play audio via it?
Best of luck
Steve