Front/rear facing dashcam in a V60
 

I am a first-time poster and here is my question: I have backup sensing but not a backup camera in my new (to me) 2016 V60. The dealer suggested I buy a third party dashcam that would give me the occasional backup picture as a bonus. I am looking at the Rexing, Garmin, and some others to install just to the left of the large bulge of plastic that forms the base of my rear view mirror. Does anyone have prior experience or recommendations about this? Is it difficult to add an accessory electric power source (looks like a cigarette lighter) under the dash? What’s inside that bulging plastic rear view mirror base? Should I get the GPS unit with the dash cam or is it superfluous to the navigation unit that came with the car? Any difficulty concealing a wire around the windshield and back to the rear ceiling? Thanks for your advice.