For the stealth hitch there is a notch cut around the component that is permanently attached that the reciever slides into. The notch is in the part of the diffuser that is horizontal so can't be seen unless you are low to the ground and looking for it.
The attached picture is taken from the ground looking up at the bottom of the Quad.
I am curious about adding the factory tow module. I would assume the wiring is there somewhere. I would just like a cleaner look then using an after market trailer wire adapter like I used on all of my MINI's and my Lincoln.