The higher capacity was only ever a Euro issue, it never impacted North American models. And it didn't cost money. There are no more coolers, or anything like that. There may be different software, ie shift points, I don't know.

Towing capacities are based on vehicle capabilities, and local regulations. Since it is a no cost option only available in certain jurisdictions, and based only on those facts, I don't think the vehicle is any different, I think it may just be labelled differently. One clue is that the standard towing capacity of 2.7t is stated simply, whereas the 3.5t capacity is limited to 12% grades. It may be as simple as a different label.

It would be interesting to know, however. One member here (from the UK) posted that the higher limit was simply a paperwork exercise, but I haven't seen other details of that.

The vehicle is pre-wired for the BMW trailer towing module and harness. You buy those from the dealer, and the vehicle has a place to plug them in. The vehicle also has some pre-wiring for trailer brakes; it still requires that you purchase a trailer brake controller, but the installation is easier than it was on previous models. If you have surge brakes on your trailer you won't require the electric trailer brake controller.

There are a few threads where members have installed Euro hitches on NA models. In those cases they purchased the NA wiring kit separately, to match their vehicles (which still required coding).

Personally, I like the fact that you can always see the hitch receiver. Form follows function. The rear apron can be trimmed so it is neat and tidy. That is what I did on my E53 and my X3.

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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