So I cut out these panels in the attached picture, was pretty simple. This was mainly just for fun and not for any real long term or practical use but did have surprising results. I got the best gas mileage I've ever achieved in this car on a really common route I take.
Traffic did not seem any lighter then normal, I went 5 miles in the city and then 40 on the freeway. Managed 65.3mpg on a route where I can really only see 61mpg at max. I have driven on this route for over 2 years now and have never seen numbers this high, did not drive any different and the traffic seemed very average for the area.
I do not really know much about this modification and the amount of efficiency you gain from this but the results did surprise me. Was thinking it could be a coincidence but even on the some what long ish freeway trip the avg mileage was hovering 2 to 3mpg more then it usually does in the conditions I was in. I think I am going to play around with these panels on the car for a little longer, maybe even on the 700 mile trip I do now and then. Again it's really just for fun.(don't worry about the paint, I use alcohol to remove the tape carefully)