Getting ready for an install with a HU, amp, components, sub. My big concern is running the power wire (4 guage) from the battery to under the rear seat. Is there a 'best' way to go. I would love to go under the truck to a point under the seat that would keep from going through the firewall and under the carpet. Any ideas? Is there a firewall location that is easy? Any other words of advice would be appreciated. Thanks.