Hey, I'm in the process of a MY06 dash swap into a MY00 GC8.
Theres some kind of computer underneath the center console, and I have no idea what it is.
Can anyone shed some light on this?
Do I need it for the swap? and do I need those yellow running wires?

Heres a pic:

http://img210.imageshack.us/img210/7319/car12.jpg

Pretty sure that's the SRS module. Typically any wires with yellow loom are part of the airbag system.

thanks, but I need you to be 100% positive :)
Can anyone confirm that?

confirmed

definitely part of the srs system. AIRBAGS! :)

Airbag module. The SRS wiring is always in a yellow sheath with yellow connectors, regardless of car maker.