I know this is a common question but i need to get an 8 gauge power wire through my firewall of a 2000 Honda Accord Coupe. Here are pictures of the inside driver side and passenger side.

 

Well you have A/C so that dummy plug is not there, are there no dummy plugs on the firewall, easier to see from engine compartment side, if not, all you can do is drill a hole, install a grommet and run your 8ga that way.

The 8ga should be run through the firewall on the same side as the batt.

Sometimes it easier to remove a fender and drill your hole into the kick panel area, then run the 8ga into the fender and through the hole into the kick panel area. 94

 

WTF, there is a spot for the clutch. See the oval shape in the padding? To the left of the brake? Drill a hole, then use a grommet. Also the power cable should always be run on the drivers side. This is because the majority of power wires are already there. Then run the RCA wires on the passenger side. This is how it is done professionally.

 

Say what???

Power cable should be run down the same side of car as the batt. is on, it keeps the cable as short as possible, never run a power cable across an engine bay, the RCAs should be run down the center of the car, keeping them as short as possible, it's all about resistance, the longer any wire/cable is the more resistance there is, so there is a drop in voltage both power and signal.
Take my word for it, over 35 years of "professional" car audio installations, from 8 Track to digital audio, consumer, demo and SPL and SQ competition systems, qualifies me as a "professional". 94