Where should you run the amp power cable through the firewall? Is there a specific place for it? 2010 Honda Civic

Anywhere you want to, but only after a complete inspection that there are no obstructions on the inside. If you mean a place where there is already an opening, no such luck, you are going to have to drill a hole. Please use the proper tool, a hole-saw with a metal cutting blade, as small as possible and still have it big enough to put a proper grommet in the hole. That is very important. Allow no space, no wiggle of the cable whatsoever with the cable in the grommet. It MUST be sealed. Please I repeat inspect where you want to drill, stay away from throttle linkage.

PS secure the cable properly along it's route, use zip-ties, not tape, keeping it away from any exhaust parts or anything else that gets real hot, do not allow the wire to flop around in engine compartment, hook it up directly to the battery and put an in-line fuse right near the battery end of the wire. If this is a super-duper amp use about 8 or 10 gauge wire, big stuff, and start with a 15 amp fuse and see if that holds, then go to 20 if it doesn't and don't come near me at a stoplight with that thing on. Just kidding, OK? I do find it very annoying when somebody it at a light beside me has one blasting and it vibrates the windows in my car

easiest way that i have installed them is thru the steering column boot or the main wire harness boot you just make a small hole and feed teh wire thru them maybe even using a metal coat hanger as a snake to do so

There's a spot on the left of the drivers side that goes up through the fender just take off the fender cover under the hood and fish it through

IMO Matt is insane.....run your power cable long with moveable parts? LMAO.....ya sounds like a safe place

Take out battery, follow the positive cable, it will reach a rubber grommet, cut a small hole with a razor in the grommet and feed it thru.. presto. Same way all the other wires get thru the firewall.