Has anyone come across any free documentation for wiring up a subwoofer & amp to a 2002 9-5 Arc stock radio head unit? I'm looking for a +12V output that stays active when using the radio/cd/tape deck. I had a friend who wired the amp to his ignition, but I don't want to be constantly drawing energy wearing out the alternator.

I'm also trying to find any help with getting a 3-4 Gauge amppower cable through the firewall. Those firewalls are really seal up.

Thanks