I bought one of these from Wassup last summer for my ‘06 Z4MR and it unfortunately did not work with my headunit even though an OEM aux kit harness did. I ended up having to solder the two together to get it working, as it appears the later model year headunits have an inline resistor board that is also a part of the OEM aux kit harness. Before late ‘06, as Wassup originally posted, the panel wiring simply isn’t plug-and-play, sadly.