Does everyone here realize that all car manufacturers have to submit their cars to federal testing for drive-by noise limits? To meet legal requirements vehicle manufacturers have to use a standard drive-by noise acceleration test conforming to relatively easily specified procedures (gear, approach speed, etcetera). The "drive-by" in this instance is the microphone used to pick up the total noise volume generated by the car being tested. This testing picks up all noise generated by the car, so a supercharged car with an audible whine component must have a quieter exhaust to stay under the maximum allowable decibels in order to pass the test.
This federal requirement limits how loud any car manufacturer can make their performance models, so those types of cars are generally tuned for a deeper sound rather than a louder sound. This is one of the reasons that aftermarket exhausts are so popular. Once you purchase a car, you only have to worry about being ticketed for breaking your local sound level ordinances.