Hey there. Im in almost the exact same boat as you
I to own a Holden VS and Iím going to be putting a carputer in these holidays aswell.
Im just waiting on the screen to arrive and I need to buy a power supply.
Ill be mounting my screen a little different to you though, ill have mine sitting above the abs/irs and antenna controls.
Although ill be keeping a close eye on your project especially how you do the wiring and dash removal stuff.
Also are you running the sound from the computer to the HU or running it straight from the computer to amp/speakers?
Good luck with it anyways