Phenomenal information and much appreciated. I picked up an '01 M roady a few months back. On my way back, less than one hour into the drive, my subwoofer blew. If anyone has replaced/upgraded their sound system I am all ears. I would prefer to keep the in-dash OEM stereo but open to upgrading with an amp and better speakers...where needed. Any suggestions on who not to trust (e.g., big box retailers) would be appreciated since this is my show car / weekend driver in the summer. I highly recommend preinspection prior to buying.