SCSI isn't necessary. The minimum requirement is MIDI.
As a paying Zuonics customer, I just want to point out an outstanding FREEWARE, cross-platform fs1r synth editor I use. It's a good example of what one can do if one is motivated.
It's made by one man: K. Take. Not only has he released an OS X version, in addition to the original Windows version, he just released a Universal Binary, Intel Mac compatible version. Now that's dedication!:
http://www4.airnet.ne.jp/k_take/fs1r_ed ... glish.html .
...Yes, the broken promises by Zuonics are beginning to piss me off...Maybe he was bought out by Creative Labs?