My sister bought a 2013 A4 Premium Plus but it doesn’t have back up camera or keyless starter. It only has a basic Concert radio. I bought a CarPlay unit and a backup camera with handle from RoadTop and installed it. Everything works perfectly although it took me a long time to figure out how to place the unit in the back since there’s no room at all, the cables are too short to even go to the glove box. Anyhow, I found the place for it and my sister love the unit, especially with the back up camera. The unit cost $200 + $20 backup camera, ship pretty fast only less than 2 weeks from China.
The problem with the concert radio is that we need to install the FPC board to the head unit to navigate carplay through the radio.
I’d installed a unit on my 2014 A5 cabriolet that has navigation 3G+ and it uses the internal microphone for texting which I like but this one needs to install an external microphone, more work but still functional.
This is a wireless system so it’s quite convenient and the connections are flawless with iPhones.