In my hunt for a RVC for my facelift A6 I came across the following site in Poland Audi A6 4S0 High Line Rear View Camera Kit With Guidance Lines - High Resolution with the cable and camera for €359.
It looked the same as the Kufatec https://www.kufatec.de/shop/en/audi/...15?action_ms=1 without the dongle.

I contacted Kufatec who were great and made an offer for me to purchase from them instead at a similar price including the coding dongle. So if you are in the market to add the RVC to a FL this is a great option.

Disclaimer- I am not sponsored by Kufatec, I'm highlighting that their offer to match competing pricing it true.