No wonder you have HUGE voltage drop. Get rid of the bass boost knob and never use it unless you know what your doing with it. Properly gain your system with a oscope or something similar.
Every car I've been in that has power windows I can hold and click the button when the window is up and make the lights dim and flash. I don't know why but it's very interesting what could cause it.
Yeah you got the CCA wire. Get some OFC. You will be paying a arm and a leg for wire at a shop.
http://www.knukonceptz.com/productMaster.cfm?category=Kolossus%20Fleks%20Kable