Got the CD player installed today. I'm guessing there are some audiophiles here, but let me just say that mp3's are compressed small files that clip off the highs and lows, while playing a CD in it's native format will give you the best possible sound.
Think of it this way, if you have a picture that is formatted as a small jpg and you try to enlarge it, it looks crappy as there is limited pixels and it does not look very clear, where as if you have a large tif file if you enlarge it, the detail is still there.
Music is the same, if you play a mp3 at low volume it will sound fine, but as you turn it up, it distorts.
So, if you want the best sound, you need nice fat juicy file sizes, and yes, you can do this on thumb drives as well...