Assistance?

[Todd Madson <crash@waste.org>]

So I've been convinced to do a one-off gig with my guitar and looping
(see http://www.myspace.com/ionospherecastingshadows if you want to
check it out).

Issue:

My studio setup is:

Guitar -> Boss OC-2 octave -> Mesa Studio Preamp.

In the effects loop:
Lexicon Vortex + TC Electronic G Sharp

The output of this feeds a digital mixer which feeds a PowerMac G5
which is running Augustus Loop and from there I can do quite a lot.

That being said, for the gig I'd rather not drag the G5 out of
my studio to the stage which leads me to consider alternative setups:

I've got the following gear I could use for a live looping rig:

Mac G4 400 with Garageband + Augustus Loop
Behrenger 8 channel analog mixer
Roland JC-120 or PA or both.

I'd like to use the analog input/outputs on the G4 if I'm careful.
The only USB interface I have is a M Audio Fast Trak which is mono,
I want to go full stereo.

I'm wondering what the most effective setup would be since I'll be
playing guitar live and manipulating the looper as I play..

I've tried messing with the rig in various ways but I keep getting
horrible digital distortion which very well could be related to the
behrenger (admittedly it was given to me as a cast off from a friend).

Ideas?  Panic?  Forget it?  The show must go on!