The side plates fill the gap left behind by the uprights nicely. The while foam is just to show me what the car will look like with a larger duck tail. The foam is about 3" high and I can't even see if from inside the car so I could go another inch or so higher and balance out the areo a little for maybe up to 120MPH. If I were to hit a high speed track, I'd then put the wing back on.