Factual error: When in New Mexico, all the vehicles have license plates on the front. New Mexico only issues one plate, for the rear of the vehicle. Also, at least one of the plates has a Q in the serial. New Mexico only uses Q's on vanity plates.
Audio problem: The episode where Michael and Alex play chicken with their cars, when returning to the road after they scrape cars, there are sound effects of peeling tires. You can't squeal tires on dirt.