Adobe Audition will do anything you want with audio sources. Heck, Nero 7 comes with tools that would probably do the job.
Unfortunately though, you can't compress the audio so that your MP3 player can play it, without loosing quality.
Your choice really, listen to the music at the sort of quality where it's perfect, but leave some music at home, or listen to a couple of crackles that most people would find insignificant.
Or, as mentionned, buy a bigger MP3 player, have your cake, and eat it.
