Hi pugmaniac - I think you're right about Mitsubishi's goal for VG's on the EVO. But they also reported a very small (Cd -.006) reduction in drag as well.
Renault also apparently achieved a small amount of drag reduction with fin-type VG's on the trailing edge of the roof of an ecomodded Logan sedan which they used in the Challenge Bibendum:
http://ecomodder.com/forum/showthrea...cy-up-179.html