Agree with King that you should go with facts. He put a couple of good links there.

Anything like the speedometer, side marker lights, etc, is easy for the dealer to do. It will cost some money, but these are essentially cosmetic modifications.

The bumper standards should be the same, but that isn't guaranteed. Note that the OEM Euro hitch doesn't reinforce the bumper the same as the OEM US hitch does, so they are working to different standards there.

I would be very surprised if your vehicle meets US emissions regulations. Each market has different rules, and the sticker under the hood will say what standards yours meets. If it meets US standards, great. If it doesn't, it may not be economically feasible to change it over. The ECM coding may not be compatible with the coding for a North American vehicle.

Good luck, but find out before you bring it in what the total cost is going to be. I once took a Ford Expedition to another country (from Canada) after getting assurances of what needed to be done to make it legal. After 6 months of so, we shipped it back to Canada to sell it because we couldn't make it compliant. The importer took some responsibility, so it only cost be return shipping, but it was a difficult process. I wouldn't try again, unless I was dealing with a 25 year old vehicle that is grandfathered as a special interest vehicle.

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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