
To show the use of wind tunnel testing, Model Sylvie van der Vaart was placed in both a 1987 and 2009 3 Series convertible in the company's wind tunnel near Munich. Both cars were then "taken up" to 37 mph to observe the effect on her coiffure—with noticeable improvement for the modern car in keeping each hair in place.
Here's more, including a video of the test!