There's only a half dozen wires shared.

The ignition wires are pulled out of the 1200 loom. The alternator loom is modified to suit the CA18's alternator. The CA18DE/T looms require start signal, ignition, 12V constant. That's it....

It's not impossibly hard. There are a few relays for the ECCS and Fuel Pump and couple of others..again, there's so many diagrams about, that these are easy too. Although I must admit they are easy for me, because I've spent hundreds of hours looking at it.

I like to wire up CA18's by starting with connectors and sensors that you are going to use. Don't wire what you aren't going to use!! eg. Aircon, Test Connectors, Wires going to the Dash, Automatic Transmission Computer, Climate Control etc. It's all hundreds of meters of useless wire. Label all of the things below with masking tape, and then pull all of the wrapping tape off the loom.

Crank Angle Sensor
Oxygen (02) Sensor
AFM
Injectors
Coil Packs
Temperature
FICD
AAC
Knock Sensor
Boost Control
Power Valve
Alternator
Throttle Position Sensor

Rip out all of the connectors that are either taped up or go nowhere. For installation in a 1200. You'll need to cut about a metre out of engine bay to computer wires, measure twice and cut once.

I like to use all of the 1200 loom to supply the power to the CA loom. The CA Loom sorts itself out.