Try this on your sedan and post if similar results

[Psychoz]

I have the 4 door sedan and found somethig that is really annoying. Get up to about 40+ m.p.h. and roll down just the back windows, when I do this I get a loud vibrating sound and weird pounding feeling in my ears. But if I roll down a front window a little bit it goes away, it only occurs when just the back windows are down and I am going over 40 m.p.h.'s.