Check the lower righthand corner of this pic:
You can see my power wires going through the grommet. That is a factory hole in the firewall. Pull of the retaining clip that is to the upper left of that hole and pull the insulation forward and you'll see it. Take out the grommet and then use a long, thin screwdriver or something to feel directly behind it about 4". That's the other side of the firewall. There's a matching grommet on the inside of the car. Just push it until it pokes through into the passenger compartment. Look up about 6" above the passenger compartment fuse box from the driver's side footwell. You should be able to see it. Just poke holes in the grommets and run your wire.
