RCW 46.04.251
RCW 46.04.251: Kit vehicle.
"Kit vehicle" means a passenger car or light truck assembled from a manufactured kit, and is either (1) a complete kit consisting of a prefabricated body and chassis used to construct a new vehicle, or (2) a kit consisting of a prefabricated body to be mounted on an existing vehicle chassis and drivetrain, commonly referred to as a donor vehicle.