Zuzax, I don't use the cigarette adaptor in my coupe, instead I went with the Comfort Indicator Panel and mounted it in the rear panel next to the battery. It provides a quick connect/disconnect and I just crack the passenger window slightly and run the cable through the window and over the seatbelt to plug it in. Pictures below....
I like the wall mount. I've got slat wall in the garage and have just been using a little wire shelf to do the same thing, but this is cleaner and I can then go back to using the shelf as a shelf.
2006 Ti Silver Z4 M Coupe
2009 Deep Sea Blue 535i xDrive Sports Wagon