BMW digital exhaust sound

There are also fairly strict noise standards for new cars such that if the exhaust was loud enough to hear with the windows up and the air running the car would be too loud on the street. I thought that on my wife's 2008 Mustang there is a mechanical connection from the intake manifold to the fire wall to port the V8 rumble into the passenger compartment. I don't think it uses the speakers in the stereo. The later cars might.