Not him, but the wire goes up into the ceiling plastic and around the side, under the plastic, and only comes out around the cigarette lighter. The "back" camera is usually built into the same unit. The advantage over what he is describing is that people often break into cars to steal the more visible (non-mirror) cameras.
Yep, other guy is correct, and wires were my first concern, but they are long and you just shim them in between the panels around and down the windows. Same with the back, but there you might have to get more creative running the wire and mounting the camera depending on vehicle.