The GEM is irrelevent nothing has to plug into it. The ids updates the stored values for what is wired in the car.
I can only talk about what i got which was for a car pre 2010.
The main loom had the big connector for the loom and a plug which went up to the control panel. My unit had two sockets on the back one of which was replaced, i left the replaced one disconnected. I think there were two other connectors on the loom, one going to the a piller into which the wiring to the mic connects, i cant remember if there was another and where it went. I think there were two separate cables which went from the bluetooth module to the centre console usb socket