There is a smooth flat area about 3" long and 2" wide just after the Drivers side strut tower. Inspect the area it's flat kind of triangular and then go into car and slide your head around the Brake pedal area. There is a relatively small extension of fabric on the Drivers side that extends upwards. You can easily pull back the fabric to expose the bare metal.It's a single layer and easily drilled and Drill the hole with the appropriatly sized Drill Bit, I would suggest buying a grommet to go around your power wire to protect the wire and the interior of your car from anything coming IN from the engine bay. Also be sure to seal with silicone or butyl rubber to prevent water from entering.then remove all paneling below the Drivers side-step and kick panel.Continuing on. After removing the kick/step- panels there is a plastic slot thats easy to run the wires thruslide Drivers chair towards the steering wheel (to have better access to remove the rear drivers side kickpanel -you dont really have to remove it, you can just pop-off the clips). there should be some carpety area underneith and then access to the trunk .
I would recommend snaking the wire from the battery all the way to the trunk, sliding the wire under the carpet where applicable. Once you are finished, replace all the kick/step panels in the way with which you removed them. Hope this helps. Its the way i did it and works/looks clean and great.
Here is the strut tower. Just north of it on the pic is the triangular firewall piece he is talking about.

here is just north of the strut tower the actual part of the firewall in the little "nook"
