I got a bike with everything left on it: speaker, strobe lights and some electrical box attached to left saddlebag guard (radio?)
It would be fun to make everything working (I know that using it on street is illegal, not planning to.) Well, using read and blue lights is illegal, I just need to replace blue cover to yellow or clear one. Keeping strobe lights is a good idea.
Speaker and microphone is a must: "Hey, pretty girl in red Honda, how about cup of coffee in my place? Pull over, I need your telephone number!"

 

Try "Retiredpolicebikes.com......