I was prompted to post this after hearing the hype about the new (and last) Aussie Commodore, the VF II. The blurb includes reference to an exhaust sound device
"... a resonator that inducts noise into the cabin to enhance the driving experience..." This sounds to me like the "Sound Racer" which has been on the market for a while. The Sound Racer is a device that plugs into your cigarette lighter and via your radio, gives you a V8, V10 or V12 sound inside your car, with the engine revs picked up via the alternator output. See
http://revvheads.com.au/ for more info and a video of the device in action. I'm thinking Christmas presents for the boys in the family, as it looks like a pretty cool gadget.