Installing Electric Trailer break controller: how to remove trim?

[miamipanther]

We just purchased Airstream sport 16 foot Trailer.

Our 12 E70 has OEM trailer hitch installed, but as always E70 still need to install the break controller to tow legally. Steallership quote $280 parts + $535 labor to install the electric Trailer break controller which is Prodigy P2 indeed. Since we already have Prodigy P2 unit passed from a friend. The only thing missing is to wire the 4 pin connecter from electric panel at rear right side of the car to the dashboard on the driver side.

I got the PDF installation guide for electric controller, it seems a fair straight DIY project, but I am not sure how to prey off all kind of trims: wheel arch trim, door pillar trim, b pillar trim, door still trim etc.

Does anyone happen to have a guide or even did so? any sugesstion is appreciated.

We are supposed to pick up the trialer on Saturday, hopefully the break controller is ready at that time.