Well, to add more of my experience to this, I replaced my problematic head unit with a properly functioning OEM and now the rest of the stereo sounds a bit better, except the sub which is rattling again. It sounds terribly muddy so I'm replacing it. Several past threads mention an improvement with Pioneer TS-SW2002D2 which is no longer available (don't believe vivid racing, tried it and got refunded). I searched for a couple days to find another shallow mount 2 ohm 8" sub and didn't have much luck. I finally stumbled on a lightly used TS-SW2002D2 for a fair price so I'm taking a chance on it. Should have it next week.