Power cable for amp.

[Blu13gt]

OK so I just traded in my wife's Ecoboost for a GT. During negotiations the dealer and I agreed that I would return the Ecoboost back to stock.
So tonight I have spent removing the sound system components. When I had the amp installed I was in a hurry so I paid someone else to do it. I'm not happy at all with the way he did the install. I don't like the routing for the power cable and I don't like how he connected the signal and audio wires.
So does anyone have a good solution that doesn't include drilling holes through the firewall for the power wire and doesn't include tapping into the wireharness near the passenger foot well for the signal wire?
I have a good solution for the rca cables.

 

[pwt's17]

I removed the battery box and pushed a wire, cut 'sharp', through the foam separating the firewall from the outside air to cabin air duct. The wire was then passed into the battery box via a hole drilled into a corner of the box. I was using 12ga. wire, but larger should not be a problem. PS. A little caulk or gasket maker where the wire enters the battery box is advised, or a leaky battery would be most unpleasant.

I tapped into the rear speakers for audio and used a Pyle PLVHL70 to convert back to pre-amp level. Not the best solution, but didn't know if base head unit had pre-amp out and didn't feel like pulling the unit out anyway.

Also, the Pyle converter, which is powered by the same unswitched 12v taken to the amp, will pass the "remote" power ON 12v to the amp when it receives audio from the speaker leads. So, no need to run a ignition On 12v wire.