FWIW I have towed our race cars regularly and heavier cars occassionally with the following: Chevy G30 Van, Chevy Tahoe, Dodge P/U Cummins Diesel. I cannot comment on the Van because it isn't a very good example but the Tahoe ('96) is OK as a tow-vehicle for the race cars but the Dodge is staggeringly good for all. Our trailer is an open "utility" trailer that I guess is 1,400 lbs and we have 3 Porsche racers (Kremer Street c. 2,500 lbs, 911 c. 2,400 lbs, LeMons 924 less still). I have used the Tahoe for some heavier collector cars and felt I was pushing its limits ... needs more power and better rear suspension.

A 96' Tahoe is WORLDS apart from a 2012.

Yikes, I wonder what mine looks like after multiple trips over Vail pass on 7% grades up to 10,600k feet in elevation at WOT 5,000 rpm and above (maintaining at least 60mph). Can't be pretty, but at least the torque converter is in lockup mode.

If you keep it in lockup and not hunting for gears it is fine, that is what kills the fluid

I have towed with heavy duty pickups and the X5 and I always felt the X5 was more stable, at least up to the 5000 lb loads I towed. It is the long distance between the rear axle and the hitch ball that kills stability on a pickup Good reason to go with a pickup and a 5th wheel

I had read up on that torque converter lock-up technique from the guy who used to post here and who tows that 31' foot Airstream. By the looks of the posts on the Airstream forum, he's still going strong with the keep it above 60mph and lots of throttle approach that I have also adopted.

Yes, that is withidl for those that want to search on his posts. 8300 lbs of Airstream over the continental divide multiple times. Tens of thousands of miles towing. Some great info. I believe withidl would take exception to some of the comments above re towing significant loads with the X5.

While he may have had success with it, I'd suggest to others who might try it that it is blatantly illegal to tow over the rated weight in virtually every state. Granted, I'm not one who follows all traffic laws especially the ones related to highway speeds, but towing at 50% over the rating of any tow vehicle is a recipe for potential disaster.

Exactly... you want to see somebody lose their house and everything they own due to a traffic accident.... that's the way to do it.

Those concerned about that liability risk should also be aware that the maximum tow rating is only applicable to the OE hitch. BMW doesn't have any tow rating with an aftermarket hitch. Same risk.