This radio system is the best I have ever seen in a car and it is seriously understated when purchasing the car. Not just slacker, but the blue tooth, ability with USB port, and creating personalized stations !!! I created a Disney station for my son. After a while it repeated the same songs and now it says "unable to play". Does this mean the songs repeated enough? This happened on another station that existed, AC/DC top 33 or something like that. Can anyone shed light as to why this might happen? I asked a very qualified rep at a store and he didn't know either. Also there appears to be a speaker in the trunk, but we don't have the upgraded sound, and no sound comes out of it. Is this created in all cars but only turned on when a person upgrades to the sound system?