Here's a few pics of the Laser Interceptor mounted on a corvette C6.
Sorry I couldn't get a full front shot of the car - I had it pulled forward in the garage as I was working on the Kart
Heads are mounted in the grille (basically the only option) towards the outer edges - similar to erikonphoenix's install.
The control box is tucked up under the passenger footwell and wired into the fuse panel. this location is easy to reach, easy to wire, and allows the alrets to be heard very well without the use of an external speaker.
Switch mounted in the console next to the traction/stability control switch.