for the amp in the back, this is what i do and recommend doing:

1. For the power cable for your rear amp, run the cable down the passenger side of your car. It's much easier to run on the side of the car because the door sill pops out with just a few snaps and you can access the carpets very easily.

2. Run the RCA cables down the driver side of the car. Again, it is easy because all you do is pop out the door sill and it is easy to access the carpet.

From the dash to the sides, the carpet should pop up pretty eassily, i'm not sure if you have a foot rest for the driver side next to the cluth( or brake pedal if you have an auto) but if you do your gonna want to take that out with an allen wrench of the right size. It is better to keep the wires on opposite sides of the car anyway because a distance of 18" between Power and RCA is recommended

Good Luck!