I just wanted to let everybody know that I got a Clarion DXZ645 deck installed and it sounds and works really good. I have my stock speakers and stock amp and the sound quality is really crips and clear.
Oh, and it has BMW orange which is an added bonus becuase it matches the interior lights almost perfectly! There are 80 colors to choose from and it plays MP3s/WMAs.
Just my 2 cents,