looks like the aero/hitch combo is not possible. this is from BMW site:

Aerodynamic Kit
Upgrade they way your BMW X5 looks and drives. Tailored to accentuate the X5's sporty appearance as well as impact its performance. A perfect balance of function and style. (Only with standard bumpers. Not in combination with Trailer Hitch Kit)

__________________
2013 X5 35i M Sport