This is all CG, so who knows if it is truly accurate or not. It seems to suggest that the Mazda engineers extended the edges of the taillights and gave them a sharp edge to control the wake better.
I have a '93 Civic that has rounded edges on the taillights - similar to MetoMPGs' car. I wonder if a trip strip would be beneficial ( A simple piece of tape is all that would be needed )
Anyways, back on topic -> the aerodynamics of the Mazda 3.
So it looks like they put some flat panels under the car too. Do U.S. cars have these modifications too ? ( This is the Euro version )