I think I went to too many rock concerts in the 70's and 80's, so my ears may not be as 'tuned', but I have the premium sound system in my 08 X5 and love it. I think one has to be careful with how you ripped your MP3's. In the early days when disk space was at a premium, many of us ripped at a low rate to fit more songs on our players. With 120GB iPods now, you should rip at the highest rate possible and use lossless if at all possible. If you have an old ripped collection, I would recommend re-ripping the whole CD library. Takes a long time, but the quality is worth it, particularly in a tight enclosed space like a car.