It's cool that there is a way to have sirens in a police car in the game. In real life police vehicles normally have a siren box, could be either Federal Signal, Whelen, or in case of medical and fire the probably have Motorola or STL (SpeedTechLights) As of now in the game it's only possible to have one siren tone in the vehicle, either Wail, Yelp, Priority, or Stinger. Would be awesome if any mod maker out there or an update for the would come out with an option to be able to cycle through the tones including an air horn.