Only if it came from the factory as a no-option item...e.g., Acura Integra GS-R or Mazda RX-7 GTU....

If it was optional, it ain't legal. If it was dealer installed, it ain't legal. If it came on *all* cars regardless of trim....it's legal.

(Personally, I'd love the option to NOT run the GS-R rear wing in ITS, 'cause I know it's all-show, no-go, as most factory "option" wings are....)