I guess it might be possible add MP3 decoding support with this, not sure how hard that would be.
Most of the older games use MIDI for the music and uncompressed digital audio for SFX, to get decent MIDI output you either need real MIDI hardware or a very fast CPU to emulate it.
Newer games often compress the audio using MP3, FLAC or VOBIS. ScummVM (060 version) supports VORIBS but FLAC would kill even an 060
I'm currently working on a new 030 version with MUS support btw...