Resurrecting this thread in order to vent.
My P5 delights me with new interior rattles almost every day. I have found and killed a few (the passenger-side dash padding buzz was particularly maddening), but new ones keep cropping up. It even has characteristic rattles for different passenger configurations: There's a set for me by myself, another for a passenger in the front seat, yet another for two or more passengers. The problem has not necessarily gotten worse since I filled my front and passenger-side engine mounts (both torn), but it has certainly changed in character.
Since I installed a new stereo with the cheese-o-matic Scosche dash kit, the radio surround buzzes consistently at a wide variety of normal driving RPMs. I will try removing it and using the Gorilla/foam tape remedy around the studs. There are also mystery rattles in both front doors, very difficult to locate.
But the worst of all is a new one: A crazy-making rattle in the height-adjustable seat-belt bracket up by my left ear. It appears to be internal, so I guess I'm disassembling. Anyone else encountered this one?