What is your question? If you have a stock amp, it is powering all of your factory speakers. The "contraption" you tapped into for the signal to your aftermarket amp is called a LOC (Line out Converter). The Sub pre-outs are obviously for the sub (This way you can control the sub level from your HU) The other outs are for if you amplify the rest of your speakers. (Which if you're leaving them stock, I wouldn't. Or you'll be replacing them soon). If I missed anything, please ask a more focused question.
