it is absolutely possible to enhance the quality of an Mp3 file with a good encoder. media encoder 9 will convert mp3 to HD .wma file, and it DOES sound better. I do this with all my favourite files.
a good encoder will enhance the peaks to a normalised level, andincrease the bitrate.
however, if you have sucky PC speakers, you might not hear the difference, and yu probably need a dose of www.avsforum.com
anyway, mp3 sucks ass after you heard High definition audio from DVD-Audio.
no musiclover with respect for himselfshould settle for mp3 quality.