WESTUPLACE,
I am assuming you are describing a car radio that recieves a digital/analouge signal?
If so, what brand is it, as I'm not aware of any manufacturers that make them for the auto market.

Let's face it, this is going to be a HUGE market once governments decide that FM analouge has had it's day.

Someone mentioned AM Stereo above, I do know that Australia introduced this in 1985, using the Motorola C-QUAM system, however I'm not sure that it really took off that well, maybe Aussie240 can enlighten us?

I'm not even sure how AM Stereo would sound, given that all of the AM signals I've ever heard on the broadcast band have been mono-aural and it lacks any top-end, regardless of any signal conditioning you do to it (as in treble and midrange cut/boost).