Just guessing, but I don't think it is probably as bad as that pic suggests.. by the look of it, the mess of wires is just someone's home made adaptor cable with connectors for the S1 harness on one end and connectors for the S2 cluster on the other end.. if you can get the correct connectors, the service manuals and some good multicore cable, I am sure you could make up your own adaptors that look much nicer..
Still not a nice 'plug and play' job though..