If you go with the K jet from an earlier car, and not the KE jet that the 560 comes with, then you can simplify the wiring greatly. Just the fuel pump and the distributor need sorting. If you go with the earlier style vacuum advance distributor, then you just need to wire in the ignition module, which is a couple of wires for power, and one to drive the rev-counter.
You could get the idle computer, but just to get it going, you dont need it. You'll just get a high idle without it.

Cheers.