So I began with the process of swapping in a MY05 dash into my MY00 GC8.
How do I go on about the wiring process?
Can I use the existing GC8 harness?
Can I keep the existing GC8 heater core?
The 05 AC's controls and plugs are different from the 2000's GC8, is there anything I can do to make it work?

I read ECS's write-up on the dash swap and he says that I should cut off the MY05 ac plugs and merge them with the GC8's harness.
And there's the problem, the wires that go to the plugs have less wires than the 05!

Also, what do I do about the gauge cluster? which speed sensor do I need? WRX's? STI's? or the one I got the harness from, the MY05 autobox 1.6L FWD?

Any info would be great,