alright if the box has a power source such as like a power outlet plug then you can buy a power inverter and then run 8 AWG wire to the trunk of the car and ground the power inverter in your trunk and design a switch up front. Then you would buy a line out converter and use it to connect the home theater sub to your audio system in the back through both of your 6" x 9"s it all depends on what you have but normally you can make most home audio stuff work in a car.