TOPIC:

I've noticed the police motorcycles in town here have very bright stop flashing strobes when they apply brakes or even when letting off the throttle. Definitely gets your attention ... wondering if anyone here has such a system on their old kawa ... or could recommend a way of doing it..

There are quite a few brake and headlight modulators on the market. I bet they are just as easy to install on a KZ as any other bike.
No, I dont use them.

is it even legal, imagine if everything on the road had them.
sorry cant help you, i just release and reapply the brakes if i think some maniac is behind me

I believe legality varies from state to state. I have seen quite a few of both around here, so likely legal in Texas.