Hi all. I'm planning on adding more subs to my 08 Lancer GTS manual with the MMCS (Navigation), Rockford, and Sun packages... the 10" sub it came with just isn't quite enough

Does anybody have any tips on running a 4 gauge power cable from the battery to the trunk? Especially suggested locations to run thru firewall? Also, does anybody have any wiring diagrams of the head unit for the subwoofer output(s) & remote turn on?

Thanks!