Aero Mods for Acura TSX
 

I just bought a 2005 Acura TSX, my parents wanted their 1999 Civic CX back.

I plan on making a solid cover for the upper grille, the new models of most ACURA cars have at least a partial cover. The bottom of the car has a full bellypan. I also read that the area between the door and the mirrors was optimized to help deliver a .27 Cd.

One modification I was wondering about was the addition of a spoiler. Many people on an acura forum have added a BMW M3 style spoiler, there is no air going below the spoiler and the trunk lid. It extends a little beyond the trunk deck.
I was wondering if anyone thinks that this would help fuel economy. I have a friend who is an aeronautical engineer and he was unsure, he thought this might be one exception to the spoiler rule. I figured it might trip the airflow coming off the trunk.

If it's a non-agressive spoiler, it can actually help.
You often see these on fuel conscious cars.
It can make the angle of the rear roofline appear shallower than it actually is (better for aero).