I got the same blackvue unit, will do the install after I get the car back from xpel/tints. I also got the MotoPark multi-safer so it keeps running for a couple hours after the car is turned off. Check out this DIY for the f30, our install should be near identical
http://f30.bimmerpost.com/forums/sho....php?t=1183385
also, there is no harm in tucking the wires just past visibility. you don't even need to take the a or c pillars off to do the install. If you did, i'd at least unplug the battery.