Pharding is dead-on.
Depending on the compression ratio, the sound quality of an MPEG 3 can be seriously degraded compared to a CD.
Just because you can fit a bunch of 'em on a disk doesn't mean it's better. On the other hand, it's in a automotive environment, so it might not make a bit of difference.
Wish BMW supported DVD-Audio and/or SACD. Now those formats are serious hi-fi.
2006 E90 325i
TiAg; Black Leather; 6-Speed Manual; Sport Package; Heated Seats; Sat. Prep; modified CDV (Zeckhausen); Rogue SSK