For what it's worth, my understanding of the US importation laws is that if an American version of a car was brought in originally, it precludes bringing a non-American spec car in later. For example, take the Ferrari F40. You would not be able to import a European spec F40 into the US as Ferrari originally built a US-spec version. How this affects the Pantera is not quite as straightforward though as there were a variety of grey imports throughout the 1980's. Basically, it could be done, but you'll need deep pockets and lots of patience with the endless banal bureaucracy of the EPA and DOT.
Best,
BT
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