That link doesn't work for me, but it is etrailer. Of the three hitches they show, two are the same, sold under different names. Those are the Drawtite and Hidden Hitch. They don't attach to the rear of the vehicle where there is any strength, but they have an ugly low hanging mount added to help prevent them ripping off the rear pan. Some owners have been fine with those hitches, others have had problems. The third hitch is the Curt. It attaches to the proper place, but without any reinforcing. That means it can twist. Again, some have been fine with it.

The proper hitch is sold by BMW. Here is an online site, a board sponsor:

BMW E53 X5 M54 3.0l > Exterior > Trailer > ES#185392 E53 X5 Trailer Hitch Kit - 71600009711

Notice the reinforcement plates in the photo. They have pentagons on one end. They go into the formed rails on the chassis, and tie it all together. That is what is missing in all the aftermarket hitches. You can also see the OE electrical interface wiring box and harness in the photo. Seems like a good price. Call and ask them when it is back in stock, or look around the web. Or buy it at any dealer, it is a standard part that they can all get. Watch out for shipping charges if you buy on the web, as it is heavy.

Good luck.

Jeff

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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