This setup came off my 4AGE race engine. It has the F3 fuel computer and IG4 ignition computer and harness to suit a 4AGE. It is set up to suit quad throttle bodies and tuned for an engine with 320 degree TRD cams.
There are also a couple of other boxes that aren't labeled but I assume are things like the ignitor. Also comes with distributor and coil.
The only reason I could think of that might stop it running a 20v is the distributor. The dissy that comes with it has a 4 tooth pickup and won't fit a 20v, the 20v dissy is completely different as far as ignition pickups are concerned.
Your best bet might be to call Haltech and ask them, it might be configurable or it might need a software upgrade. I'm affraid i don't know that much about Haltech...