Doing a lot of driving in the wagon and wanted to utilize my V1. Finally got around to doing the same type of setup I did in the S5. There is obviously no rear deck in the wagon, so I cobbled together a mount that utilizes the center headrest, but other then that, the principle is the same as the S5. Now, I can just move the actual V1 unit between cars when I want to. The mounting system is common, and each car has it's own remote display, remote audio/power unit, and wiring.
display (that other wire is for the remote start antenna that came with the car, the v1 wiring goes through the rear view mirror wire cover, across the headliner, down inside the a pillar, and to the hardwire unit down by the fuse box)
audio control
rear center headrest mount (this gets hidden when the headrest is retracted)
the actual unit
and for reference, the S5 setup