[ErVikingo]

Here's some relevant links. You'll notice no mention of what to do with a car 25 years or older (that I could find anyway).

http://www.nhtsa.dot.gov/cars/rules/import/web_RI_list06202005.html
DOT : http://www.nhtsa.dot.gov/cars/rules/import/
EPA : http://www.epa.gov/otaq/imports/quikover.htm
US customs : http://www.customs.ustreas.gov/xp/cgov/import/