I’m new to this forum and I got a few questions for other owners.. I’ve been wanting to add the Rockford Fosgate P300-12 powered sub to my car and I would like to keep my factory radio. Would it be possible to just hook the sub to a rear door speaker? I don’t have the pioneer system. The description said I don’t need to run rcas or a remote turn on wire but this would be my first system with a stock radio so I’m confused. I’m planning on using either 8 or 10 gauge for power and ground. Can anybody shed some light?