Here is a visual of the RS7 exhaust.
Hitches for xBs use the three bolt holes on the 2 main structure frames on each side to mount the hitch. So, the exhaust and hitch try to occupy the same space, but only one can fit.
On a "normal" routed xB exhaust, the final pipe goes straight back from muffler to the bumper. The 7 makes an "s" bend to the center.