To give the driver a better feel for the engine, an exterior recording of the M5’s motor plays through the car’s stereo. The precise sample is determined by engine load and rpm. Some of the real engine notes are still audible to the driver, so the recording is more of a backing track. BMW says the setup helps the driver shift by ear and reduces the chances of bumping the rev limiter when using the full rpm range.

One of the features of my new car that I wish I didn't know about. (No, its not an M5.)