We decided that it was mainly for 4 doors because the airflow is more disrupted off of the roof of a 4 door compared to the 2 door. On civics I know the slope is much less on the coupe thus making the air flow around it better, I dont see it helping you much
__________________ Current Stable
GasSaver: 2000 Honda Insight Silverstone w/AC 65+mpg
Track Terror: 2002 Honda S2000 Gran Prix White- lots of mods - 28mpg
Beater: 1988 Honda Civic DX Hatback - Stripped - 30mpg
RIP: 1996 Honda Civic LX 42mpg - you will be missed
Thanks for pointing this out. I remember seeing Ziploto's "Casper" in other posts, but I hadn't found the vortex detail. My SW2 has the "corrugated" roofline of a wagon, so I was wondering what the optimum position would be (even for so little benefit, it appears).