I recently sold my 2012 Audi S4 (no nav) and bought an adapter to plug into the MMi port which would allow me to connect my phone wirelessly to the car's bluetooth and stream music. It's a Blackberry Bluetooth adapter that was re-wired to work with my Audi and it works 100% of the time. The part number on this Blackberry adapter is ASY-16007-001.

Taking best offers as this was custom made and should work in most Audis. NOTE: the cord with "UP" on it does NOT plug into anything. It simply sits there.