Everything you just said is right on the money. But if you take all 14 outputs into an amp,you will still end up w all the same frequencys that the amp is putting out .sound will sound the same but louder.Their is another way.I have done 2 this way and am on my 3rd as we speak.1.There is a fixed signal at the amp that can be taken into a preamp eq(audio control eql) them you must boost this signal extremely hi . 2 .them you will run this fixed signal into a Pre amp that has a remote volume control(audio control mvc1).3 then run all signals to the new 6 channel amp and change front speaker to 2 way components (mbquart q series). 4 .add 3 way mb quart passive x overs to all rear speakers . 5 build custom sub through the arm rest. Mount volume control were the hazard switch was and move to center console(hazard switch)