I recently bought a 2004 Grand Prix, and was definitely excited about the working cd player, which my grand cherokee has lacked for a very long time. BUT it tells me to check the disc when I insert a burned disc. It plays store-bought ones just fine. What file type is able to be played by the 2004 Grand Prix GT cd player.. and since I'm thinking about buying a 6-disc out of a GTP of the same year, that one too?