Since the game allows you to revert to text mode instead of voice... once you've started, how does once view the floppy version of the intro without the voice?

As far as I know no way to go to text intro from within the game. You can try changing the settings through the resource.cfg to change to alternate drivers that doesn't use digital sound (this will eliminate any digital sound effects as well, so be warned). Added bonus note with this if you play around with EGA or monochrome modes the Monochrome boys will notice this and say something that matches the settings when you encounter them.

Actually, SQ3CD although it has text mode for the game. The text is not the same as the floppy version.

There are also one or two puzzle differences between the floppy and cd-rom, as well as changes to the shops at the Galaxy Gallaria. The intros are not exactly the same in the floppy and cd-rom versions either (mainly differences with the alien that vomits outside of the BAR, the alien doesn't die in its own vomit in the floppy version).