I found this abstract talking about the purpose of cabin air extractors:
http://deepblue.lib.umich.edu/bitstr...t18_report.pdf
From the abstract, "air extractors are installed in the vehicle to relieve the steady state airflow from HVAC or the pressure pulse wave from the door closure event. The air extractors also serve the purpose of allowing airflow so that the HVAC can defrost the windows properly."
What I wonder about is whether or not the fix being mentioned is something that can be retro-fitted or will only be available for future models although the road noise isn't something that bothers me.