sorry about the waste of time comment!!!! cannot ride with my rear windows down it produces a god awful rumbling sound like there was an attack helicopter hovering overhead and the steering wheel and front end start to vibrate,I have air which I do not use all the time.am taking it back to the dealer today 7/2/12.and gripe some more I have been looking on line to see if there have been other 's with this same affliction but as of this ranting I have not