Well thats what I was trying to say. I remember seeing a post somewhere (thought it was here) but I couldn't locate it. It was about the radio increasing volume when your speed increases. I believe it was independent of the actual gear but you were talking about gears so I got confused. And somebody said that they modified it somehow to make it work better but it looked like quite a project (i.e. hooking up components to speedometer circuit).
EDIT: It seems with a little more searching, I managed to find the info
here
The only thing about this hack that I don't understand it the GAL setting. He says to look in the radio manual, but I don't have one. Is that separate from the car manual because it's not in there? Also has anyone performed the cabrio relay hack?