Well I'm constantly reading about people and their pioneer grounding issues, so anyway I had my deck out and decided I would ground the casing (its a KDC MP7028 if I remember correctly) and I will say it was worth the two ring terminals and the 8 inches of wire. I have a separate switch for the remote for my bass amp, before the new ground if I was listening to for instance an AM radio station, with the bass amp on it would give a nice little hiss, flip the switch and the noise was gone. If I flipped through tracks on a cd I would also get a little sub noise going between tracks and it was especially loud at the beginning of a cd. So in conclusion, all that annoying noise is gone with a simple ground to the head unit. If you haven't done it, try it and see if it helps take a little noise out (which is quite contradictory to what most of us are all about)

cut cut, scratch, tweak, t t, BOOOOOOM