I don't see it being a difficult rewire but "easy" as in snip, snip, crimp, crimp no.
Do it right though. Run your ignition wires through the existing sheath and use proper mating JST connectors to connect to the existing harness.
Curtis is right. I put a HI-4 in my bike. the only problem is finding the tac wire from the ECH wire pile and connecting it to the brown HI-4 wire. I finally spliced it in from under the tank.