Today I'm going to wire up my car for an amp. What's the best way to go through the fire wall. I know there is the plug in the firewall. But I think that is too small and too far away from the battery for 4 gauge. I was thinking about running the wire from the battery underneath the tray through the passenger side firewall and then down the passenger side. Has anybody done this or is there an easier way? I don't mind drilling a new hole and getting a plug for it.