Paul,
Maybe contact member 'Daniel #9191' he has just imported a GT5 from Canada and can probably provide details of the paperwork trail. Also read closely his post directly before yours in the "Ownership Issues" forum as by his account you won't get it into the US until it is 25 years old, so be prepared for a struggle.
Having said that it would be worth contacting Kirk Evans of Amerisport an original importer of GT5-S cars. His website is www.amerisportindustries.com e-mail: kre1[at]adelphia.net or telephone; 419.344.8148
Good luck
Julian
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