u can get the latest mad plugin (0.13) for winamp below:
http://www.mars.org/home/rob/proj/mpeg/mad-plugin
no doubt that because mad attenuates clipping there's less distortion. if the distortion levels are high enough the results would be very comparable from other decoders - i would go with either mad or the fhg decoder from winamp 2.22, but if you want to avoid clipping, use mad