i have an 02 SC430. I have a "vibration" niose in my passenger midtone speaker. it only wakes up during deep tones on talk radio. the service manager at Fremont Lexus says that this is a known problem with this sound system, and that there is nothing they can do about it. This is the same guy who has tried to fix a passenger side door rattle (cooincidentally, sounds like it is coming from behind the midtone speaker) 4 times, and can't fix it. since it is intermitent, it always is quiet during my post service test rides, but soon after they turn me loose, it wakes up again. I have called Lexus North America, and they just send me back to this same service manager. I am living with both noises, but curse Lexus everytime these noises wake up.