At this point nobody seems to know precisely what you get with this option. On the one hand the description refers to sound within the cabin only - whereas Euro spec cars apparantly have a sound generating speaker in the exhaust system taht can be heard outside too.
The concensus is that the GTD has always had the 'Sound Aktor' gizzmo anyway - so there is also a debate about whether its simply this being made in to an optional extra....
If you figure out can you let us know!
