I made a write up with how to extend the harness... I can't seem to find it, so if anyone has the thread saved somewhere, please post it here as well. I went to Frye's and got a couple of different sized spools of wire, a fancy wire stripper, and a bunch of heatshrink.
This is what I did with the Aristo/2JZ (after a few swaps, you start to find ways to do things better/faster). I hope it helps ya out some.
Went kinda like this... took us about 3.5 hours, including prepping/staging stuff. I did not extend the Aristo body plug, 'cause you really only end up using a handful of those wires.
Prepare the wires used to extend, measure and cut to same lengths... (Tip: Place shrinkwrap on them and then strip)
Then separate wires into bundles (maybe 10 at a time) where the colors of wires will not accidentally be mistaken for another... Cut & solder one or two bundles at a time
After you've soldered and checked the connection to be good, hit the shrinkwrap with the hairdryer.... and there U go!