The stolen cars are being transported "fresh from the factory" and should not have license plates.
When the patrol car was chasing the truck, one of the brothers threw tires from the bed of the truck. Several times, the patrol car ran over the tires which could have damaged the undercarriage. In fact, the car ran over the tires with no apparent damage to to the vehicle and the tires that collided with the patrol car seemed almost to disappear.
The carjackers, Dan Mathews, and other characters refer to checking the mileage of the vehicles on the "speedometer". Mileage of a vehicle is shown on the odometer, not the speedometer. The speedometer only shows how fast a vehicle is moving when it's in motion, not the accumulated mileage.