The noise is coming from the back of the coupe and is a nasty rasping noise at high RPM. The heat shield that lines the underneath of the car between the rear exhaust and body appear to be the source of the noise. My wrong assumption...When you said air box I thought you meant putting something between the sheild and the body. I just hit 1200 miles, yes I'm smiling big time, so I'll see what the dealer can do about the noise.