Installing a Blackvue is super easy in the Tesla (installed one in both my Teslas in about an hour) - first one took longer because I had to figure out routing. Once I figured that out, the second one took about 20 minutes.
Clip the power wire about 12" long, wire it into the little connector under your microphone grill for power. String the rear camera wiring in the trough in for the pano roof if you have one (if you don't have Pano roof, you'll have to string it along and under the trim on the drivers side. Where the rear C pillar trim mates up to the roof, string the rear wiring through it and into the trim in the hatch and along there until you place the camera in the middle. You'll have a wiring stringing from the hatch to the C pillar in the corner, but it's barely noticeable and not in the way of anything. You can't see it while driving, only when opening the hatch from the rear.
Easy as pie.