If memory serves, there were some issues with the WinAmp MP3 decoder doing a bad job, but from memory that was around version 1.8 or so. I heard criticisms on and off since then so I don't know (and I imagine they would have fixed this up now). But if I were wanting quality decodes to WAV format then I'd use LAME.
The WinAmp decoder was built for speed, like PKZip.
Have fun,
Paul
_________________________
Owner of Mark I empeg 00061, now better than ever - (Thanks, Rod!) - and Karma 3930000004550