can I use MAD to fade and split an MP3?

I am interested in using MAD to fade out at an arbitrary point in an
arbitrary MP3 file and then potentially split the file at the end of
the fade out.  Is MAD appropriate for this?  If not, does anyone have
suggestions for other OSS libraries that can assist with this kind of
thing.  I could probably use sox after ripping the file to wav with
mplayer, but the roundtrip conversion from MP3 -> WAV -> MP3 would
probably degrade the file significantly, so I would prefer not to do
that.

Thanks,
Chris