[ChrisZang]

if your camera looks like the one on amazon.com then you could mount the camera above the license plate, that means that you need to drill two little holes for the screws
These are the only holes you need
Behind the license plate is a hole through which you can route the cable and then you need to route it from there into the trunk, if you raise the rear wing you can do it. I then routed the cable inside the rubber grommet which isolates the trunk towards the front of the car.
There you will find a large round rubber seal at the rear "firewall" through which you can easily poke a hole. If you don't figure it out ping me and I take a few pictures.
Don't forget that you need to tap into the wire for the reverse light so that the Pioneer switches to the rear view cam when you back up.
And last not least: Connect the +12V to the switched power, not to "always on"
I did that by mistake and was fighting a dead battery for weeks until I figured out my mistake.