M1Tanker,
yes, I bought the adapter from Touratech (EUR 30,--, probably the same as the one from BMW) and plugged it into the connector below the oil cooler. I am using this since January this year; I am quite happy with it.
I never have noticed any losses in eletrical energy when the bike is turned off. Of course, my bike normally is rain protected in my garage, but even in strong rain for whole nights there never was a problem. Why do you expect electrical problems? AFAIK the Zumo connector (that plastic part with the many needles) has no electrical components (beside the wires), so where should the energy go?
Greetings,
Alex