Oddly, my mirror glass itself is rock solid at all speeds. Just makes the cheap sounding vibration when closing the door, and occasionally when hitting a bump the right way on the road.Well I was able to fix my gas LE cause of the lose screw, but it still rattle from time to time as well as vibrate a bit on highway. My Hybrid LE however, the mirror are rock solid and don't even move on the highway. So there is def something wrong with people that have rattles or vibration on their mirror, since based on my experience, well they all do it. Hoping for you they can fix it perm.