You use a program called Xbox Media Player to play those mp3's. But some mp3's work, some don't - and you don't get any playlist support or anything you expect from a normal mp3 player.
And as for the DVD problem, I don't see why people would want to mod their box and not use the built in hard drive and instead boot everyrhing from discs, which the DVD drive has problems reading anyway. My advice is to setup Evolution X on the hard drive, boot the DVDX2 from there and not have any problems whatsoever.
