The centre of gravity (if the load is distributed equally front/rear) appears to be about 24" from the receiver pin, according to the drawing in your link. The stated capacity of 450 lbs may be OK if you had a frame-mounted hitch, but the BMW hitch won't hold that safely; it is rated for 600 lbs at 8". At 24" to the load centre, the capacity comes down to 200 lbs, if you have the OEM hitch. Deduct 50 lbs for the carrier, and you have a design capacity of 150 lbs of cargo. If you are under that load, you should be fine.

__________________
2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue