While you can not play MegaVoices, you can convert midis (and styles) to use them.

Programs such as MidiPlayer change the voice and rescale the velocities etc, but do not add the sound effect tracks (fret noise, etc)

MegaEnhancer by Yamaha does the conversion and does include some effects (I am not sure if it does it for all MegaVoices or only some). It only works with mid files, but you can use StyleMaker to use it with styles.

Regards,

Michael