The two hitches both bolt to the bumper structure, using the same holes as drilled at the factory (becomes part of the bumper, beneath the cover), with the angled support bolting to the crossmember behind the rear differential.

With a load being placed on the hitch (via a trailel tongue or a cargo carrier), the hitch tube will be leveraged downward, while the upward-angled support will be cantilevered up against the crossmember, adding more capacity, and stability. Both the 74592 and 13162 hitches are rated for 6000lb towing, with 600lbs tongue weight (with Weight Distributing equipment, as I ALWAYS use).

Nominally rated as Class III, they're in actuality midway between a Class II and III (3500lbs and 8000lbs). Regardless, I'd say that they both meet or exceed the towing specs in the owner's manual, at least for my '01 E53, with the M54. If you need more, get a 3/4 ton or bigger pickup, and a Class IV hitch!

__________________
01 BMW X5 E53,3.0i-5L40E, 7/13/01
topas-blau,Leder-grau,"resto-project car"

Here:
14 Lexus ES350,3.5L-U660E
09 HHR Panel,2.2L-4T45E
04 Chevy 2500HD,6.0L-4L80E
98 GMC Sierra 1500,5.7L-4L60E

Gone:
66 Chevelle Malibu 2dr ht.,327>441c.i.-TH350>PGlide/transbrake
08 Cobalt Coupe,2.2L-4T45E
69 & 75 C10s,350c.i.-TH350
86 S10,2.8L-700R4
73 Volvo 142,2.0L-MT4
72 & 73 VW SuperBeetles,1.6l-MT4
64 VW,1.2l-MT4
67 Dodge Monaco 500 2dr ht.,383c.i.-A727
56 Chevy 210 4dr,265c.i.-PGlide