I think a dashcam is a must with the amount of insurance scams nowadays (dashcam footage means many instances of insurance companies saying "50:50" even though you're not to blame just to reduce their costs, goes away e.g. they can't argue with video EVIDENCE of some knob ploughing into you from a side road because they pulled out without looking, witnesses or no witnesses) <--- happened to a friend who had no dashcam and no witnesses so they couldn't fight it, their premiums went up as a result
I have a single front dashcam in my F30 (Viofo A119 - 1140p30 wide angle recording on a Lexar MLC 32Gb microSd (3.5ish hrs recording)). Better than my old 1080p Transcend DP (I find it's a crisper image that's easier to read numberplates from due to the slightly higher res - for instance, 1080p allows accurate numberplate reading from just over 1 car length away but 1440p can increase that distance to just over 2).
Comes as non-GPS version (mine) or a GPS version for about £10-20 more. The only extra I got was a CPL (circular polarising) filter to reduce dash reflections.
Placed it to left of rear view and routed wire along headliner, down and across A-pillar, under glovebox and into accessory socket.
Turns on when car unlocked and door opened, turns off a few minutes after closing door/locking/alarming it
(or to be precise, after having just timed it using the dashcam itself, the 12V socket goes out exactly 3min after the doors are locked - which isn't an appreciable battery drain):
Mounted snugly behind the rear view mirror
Routed up in headliner, down A pillar and behind rubber trim on side of dash
Then placed into accessory socket for power
Looks inconspicuous enough...
Literally took about 5 minutes to install and cost
< £100 all in (so I would recommend doing it yourself as you can choose from the hundreds available and not have to rely on what the installer is trying to sell you).