[9146racing]

they are testing the range, performance and direction of the airflow of the vents.
this happens early in the production design phase, so location or size of vents can change and the overall interior design can react to the results. next would be testing the acoustics in a prototype, (how much wind noise do you hear while driving) and noise and airflow in different speeds while the side window is open. one of the results you find on your 928 is the little black triangle you can find on the side windows. take them away and the draft is incredible while driving with an open window at certain speeds.

hope this help,
Hans