I have to run 4ga for my 2 amps, so what I'm probably gonna do is buy a real nice grommet like the PhoenixGold one, and just drill a hole in the firewall and put my own grommet in there. That way (as 240meowth said) I'll have a spot for my power wire, and my fog light switch wires (once I get them)
It'll look real clean and keep the seal.
looks like this:
