where is a good place to run the power wire from the battery into the cabin of my car. i'll be using 4 awg wire and when i pull up the carpet in the passenger foot area, i found a really big surprise with all the computer stuff there.

 

Under the passenger foot area is actually the factory amplifier to the stereo, not the computer. Although the battery is on the passenger side, you could run it along the fire wall to the driver's side where there is a rubber plug. You can remove that plug, drill a hole in it the size you need, and then re-insert it. Or, you could drill a hole in the firewall on the passenger side and use a plastic grommet that usually comes with 4gauge wire if you purchased it for a stereo installation.