I just purchased an 89 M3 with 61k on the clock. First off, the lower left side of the windshield leaks, which runs straight to the dead pedal. But there is this annoying humm/rattle that happens around 4000 rpms'. Could this be the same problem? It sounds like it's coming from behind the instrument cluster and is a little less pronounced when making sweeping right turns. There also appears to be a problem with the sunroof. It will close but leave a 1/2 inch left open, where you have to press the button again. Is there anything simple to fix this? And is the rear seat the same size as an e30 325? Mine is perfect aside from some stiching coming loose. New to the M3 world! Help Please!!