i'm sorry, that was a brain fart. the dual 4 ohm driver would be wired in parallel for a net of 2 ohms. that would be connected to one channel of the inuke3000dsp for 1100 watts (the manual says 1520 watts, but that is high).
the other channel would be left empty as the upgrade path.
wiring a driver in parallel is easy. one wire to connect red + to red +, another wire to connect black - to black -.
your amplifier will then hook up to one set of connectors, again red + from amp to red + on sub, and black - on amp to black - on sub.
so after it is all said and done, all the reds will be connected and all the blacks will be connected.