That's a neat concept, but I worry about the liability of having a customer install a gadget on top of their gas pedal. Wouldn't it be easier and safer to plug into a 12v and measure RPM via current fluctuations, the same way the SoundRacer does?
I don't think they actually made the gadget. It's more of a slap on the wrist towards the German cars with their electronically simulated engine sound. It's just an AD for the Mustang.
At the price point they sell in Europe, it's pretty cool having a 435HP natually asperated V8 instead of something smaller and turbo charged.
Like I said, they didn't acually make the gadget, they were just mocking the equivelently priced european sports cars. You can have a turbo four with the "gadget", or you can drive the real thing.