Downloading mp3's - help please !!!

[anabeces]

1)I want to RE-download my whole mp3 collection in a higher sound
quality eg.320 kbps

2)Are there any programs (or addons/plugins to programs such as Kazaa
Lite) that allow for filtering searches. So when I do a search for
a song, only the high quality ones show.

3)What factors make for high quality mp3's ??? other than kbps

Thankyou in advance.


PS: I just bought the NOMAD Jukebox Zen NX, it is awesome.