I know that there have been similar threads, but none that quite aswer my question, sorry! I've jsut bought a brand new 307 Sport, with what the manual describes as an LD4 head unit with 5 CD changer. Most of my music is on MP3 CDs which my previous car stereo played no problem. The manual for the LD4 clearly states that it plays MP3 CDs, but I simply cannot get it to work. It just spits the CDs out after a short time. In the Changer display, it describes them as "Unplayable." Any advice?