Thanks Carlos.. that was an excellent reply, full of good information I can look up as time allows.

The problem must be in the setup of my GI-20, because the Godin sounds amazing when played through the original Roland GR-1 guitar synth pedal. But when I try to play it through a Roland XV-3080 rack synth using the GI-20 as interface, it doesn't sound good at all. (and it SHOULD sound much better)

I'll plug in the settings you recommended and try again.