Many auto manufacturers do not allow new cars made for use in the US to be exported. Dealerships may have you sign an agreement not to export the car. If you do and still export the car then you breached the agreement.
Used cars can generally be exported. If the exporter does so on a regular basis, he may want to consider a wholesale dealer license.
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This isn't my field, but I believe that there are federal export licenses, and possible duties, when a car is shipped overseas.
If you feel you may have exposure to liability, consult an attorney familiar with tax law.
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