FirebirdTN:
Thanks!!
I belivie your plans will be prefect!
I hoped that I could skip the amplifier for the "speakers" but I guess I need to use one anyway. I do have a old amplifier I can try with, if its working good I can get one fresh

Maybe one of those amp9 kit, hard to "build"?
Should be great to have everything in the "home build stereo"

.
I have seen many posts saying that it is nessesary to install a Volt Regulator on the "amp on" wire. Because the stock amps uses +5V, and ordinary stereos using +12V. I guess in my case the M2-ATX does too. If you not use one, you will get a "thump" when power on.
Im not sure I understand what you mean by "crossover".
I guess that the trunk subs get there signal from same RCAs after the aftermarket harness is installed.
So 500/1000 seems to be identical.
Thank you again!
Daniel