EPA, DOT & CBP import requirements
The EPA has crafted a comprehensive manual (accessible on their website) on the emission regulations when it comes to the non-US version vehicles and US-version vehicles driven overseas.
Also, the US Department of Transportation has a set of Federal Motor Vehicle Safety, Bumper and Theft Prevention Standards which all vehicles have to pass to be imported from Europe.
Finally, the US Customs and Border Protection can ship your vehicle back to Europe if it doesn’t pass its smog, safety, and bumper check.
To be able to import a car from Europe and register it in the US, you must make sure it complies with all the standards and passes all the above-mentioned checks.
If you are importing a classic vehicle, there are specific differences. For instance, if the classic car is over 21 years old, it doesn’t have to comply with the EPA requirements. Furthermore, for cars over 25 years old, there is no requirement for compliance with DOT’s Federal Motor Vehicle Safety Standards.
Important info to Ship a Car Overseas

Cars like this one can be imported to the United States if bought outside of the border following the USA’s specific guidelines.
No vehicle can leave USA if it has a lien on it. This means your car has to be paid in full. The only individuals who can ship a car overseas and still have a lien on their vehicle are US Military and Government employees/contractors. For these individuals, a letter of authorization from the lender will have to be issued to get through US Customs. Otherwise the vehicle could be considered stolen.
If you bought a new vehicle, your name must be listed on the front of the title as the registered owner.
If the vehicle has been sold, then both the buyer and seller have to sign the back of the Title in the spaces as detailed on the back of the Title.