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13 Import of Vehicles & Spare Parts
13.1 Importing into America

The following is an excerpt from a U.S. government publication entitled “Importing A Car”:

Nonresidents may import an automobile or motorcycle and its usual equipment
free of duty for a temporary stay to take part in races or other specific purposes.
However, prior written approval from the EPA is required and such approval is
granted only to those racing vehicles that EPA deems not capable of safe or
practical use on streets and highways. If the contests are for other than money
purposes, the vehicle may be admitted for 90 days without formal entry or bond if
the Customs officer is satisfied as to the importer’s identify and good faith. The
vehicle becomes subject to forfeiture if it is not exported or if a bond is not given within 90 days of its importation. Prior written approval must be obtained from DOT. A vehicle may be temporarily imported for testing, demonstration, or
racing purposes.

With rally cars being capable of “safe and practical use streets and highways” this
complicates matters, and we recommend that you research the matter carefully. Another encouraging part of the document states “These vehicles may be operated on public roads or highways provided the operations are an integral part of the test.” Also, Sandblast Rally, giving no prize money, does fulfill the “contest for other than money purposes” clause. The Supplemental Regulations explicitly state that no prize money will be awarded.

The full document is available on the official government importation web site:
http://www.cbp.gov/xp/cgov/travel/vacation/kbyg/prohibited_restricted.xml

For the forms to import a car, you must deal with the National Highway Traffic Safety Administration, available here:
http://www.nhtsa.dot.gov/cars/rules/import/Racing/
You may submit these forms yourself, or have a customs broker (in the U.S., in a port near where the car will land) do it for you. You do not need to have a NHTSA “Registered Broker” process this paperwork, as those businesses deal with cars that are imported for sale.