This is what I'm using to install my Z110BT into my B7.
http://enfigcarstereo.com/shopsite_sc/s ... AD003.html
If you have RNS-E then you need this one.
http://enfigcarstereo.com/shopsite_sc/s ... AD002.html
You will also need this for both o them,
http://enfigcarstereo.com/shopsite_sc/s ... RLEAD.html
I'm doing my install next week. This adaptor will allow you to keep stereo controls also....that's the main reason...but as stated on the website...this adaptor will get you
"Audi steering wheel control interface with switched +12V, illumination, Speed Pulse, Parkin