[MetroMPG]

apgrok1 - There are lots of examples of roof extensions (on hatchbacks/wagons) and trunklid lip extensions on sedans which reduce drag. Some of them also happen to reduce lift at the same time. Yet others reduce lift at the expense of higher drag.

adbso - I think you're right in that the goal of the Mitsu engineers was to get more clean airflow to the decklid spoiler on that car. That said, if the spoiler wasn't there, the net effect of the VG's would have been to very slightly improve Cd and reduce fuel consumption.