You have a few choices here. But 8 gauge wire is awful big to try to hide.
1. You can run all the cables under the carpet in the middle of the car on (most likely) the drivers side.
2. A better way is to make a hole in the floor, find a rubber grommet much like used in your fire wall for the speedometer cable, and run the wires under the car and run them through the front end support brackets up to the battery.
Personally, I'd live with the line under the carpet. But you'd have to run the wire through the same hole as the speedometer cable or drill a new hole in the firewall near it. Remember to always keep those sharp metal edges of a new hole off a moving line by putting in or making a grommet of some sort.
I hope this helps.