Originally Posted by fabrio.
You use the foam spray for fill the back bumper, I am interesting at your experience
Yeah, I will test that too. I don't expect the results of that to be as good as covering the entire back area, like some have done. I plan to test it, first, by filling it in with cardbaord. Frankly, I think that the air has lost a lot of energy by the time it reaches that area, so there will be some
advantage. But whether or not it is so marginal that it is unmeasurable is anyone's guess. (Hope I'm not using too many English idioms for an Italian to understand!)
Like I said before, all the changes I make must be unnoticeable to my wife, since this will be her car in the future. If/when I do use the foam, it will be way in the back, only, so that she can't see it. I will also paint it the color of the car so that it doesn't stand out.