[Lurayfarmer]

I'd say go ahead and use the full harness if it is really clean and solid. As to wiring in extras, you won't find a made-up harness for that. I would add the wiring you need as you install the main harness so you can run the wires inside the same conduit. I do recommend enclosing big bundles of wires in plastic loom. Just a little extra insurance against shorts and it's invisible under the dash.