It would greatly depend on what you are importing, but chances are it will not meet the DOT standards. You can import a car temporarily, I believe for a year at a time, as race/show car, but it will not be street legal. You can import any car, regardless of it meeting standards or not, if it is 25 years old, thus being allowed under the historical car provision. You can also import any vehicle for personal use by a nonresident, but this cannot exceed one year.