RE: Stereo qusetion
Just a guess but on premium factory systems they reduce the bass output to prevent blowing out speakers so this may be a preamp out for an add on amp/speaker.
__________________
For I know the plans I have for you," declares the LORD, "plans to prosper you and not to harm you, plans to give you hope and a future. Then you will call upon me and come and pray to me, and I will listen to you. You will seek me and find me when you seek me with all your heart.