You must be talking about the ZXs, which have a talking thing instead of a buzzer or dinger. IMO, those don't belong on an S30 car. Even a dinger seems wrong IMO.
I got a buzzer thing from NAPA. It's just a 12V buzzer, like you can buy from Radio Shack, with alligator clips on the ends of the wires. You're supposed to clip it into your fusebox, but on a 280Z the light fuses are all hot all the time, and so are many other fuses, so you will have to hook it into the headlight switch connetor & ignition switch someplace.
thx