i have dual frontal dams, where the original dam follows the wheel well liner and curves back, (it doesn't curves up on the right side, just back, but the angle of the picure makes it look that way) this is made from thin coroplast, and it's not really strong enough, as it fonlds back at high speeds. i know this as a tiny bit is grinde away by the tire after a long highway trip. i'm not sure if this is entirely bad however as in that position it will seal of the front of the wheelwell and the gap between the tire and the front bumper
in front of this dam i build a new dam at approx 45 degrees angled out. this dam is also larger in front of the tire
my inspiration for this is this:
i'm not sure if it's perfect or if flat wouldn't be better, but so far my fe don't seem to suffer and the car feels lovely stable at highway speeds.
these are my rear dams, made them small and as an experiment, buy gluing two plastic L brackets to the underbody and taping coroplast to it. they seem to help as my average FE is pretty good since these where on
finally i have rear strakes behind the rear tires, simple L bracket that are screwed to the bumper... inspired by the previous prius.
finally i have an undertray covering the entire area in front of my tires, and i'm looking to extend this to cover the engine bay.
i also have my front grill almost completely blanked off from behind