Project 3.4 Camaro

Sick and tired of pissing around with this ECU swap, I just want my gd car back. I am either going carbed, back to my old setup since apparently only my LIM had cracked so my MIM and UIM are still usable, or probably going to swap in a 93 3.4 ECU and harness.
My questions are, where the wires for the engine harness exit the ECU, two groups break off and go up into the dash, while the rest go through the body out into the engine bay. What are the ones leading up into the dash for if not the engine? Or do they simply get to the engine bay via a different hole in the car body?
Lastly, probably a dumb question, but how do I remove the whole dash assembly? Even if I didn't have to pull it there are some obsolete wires I wish to remove(ie. stereo, hvac)

Six_Shooter

iTrader: (2)

The ones that go into the dash are ignition feeds, VSS, ALDL, shift light, etc.