Hey Nicholas, I've got the exact same thing going on with my car. Lumpy idle (not missing or anything like that, just makes a 'breathing' noise maybe once every 1-2 seconds consistantly).
Thought it might be my timing, so I bought and hooked up ECUtalk, and my timing reading is all over the place between 0 - 15 deg as well... I can't figure out why!
Next thing I'm going to try is check/adjust the timing at the CAS, just so I know what it's set to, and just to rule it out for further problems.
I'll keep you posted.