I've got a 2005 Prius with the upgraded 9-speaker, CD changer and JBL amp under the passenger seat. I want to connect the powered sub I've got, and place it in the back storage area. I assume I can connect to the standard battery located on the right side behind the wheel for power? Does anyone know which wires I can tap into on the JBL amp for the speaker-level inputs, and for the on/off power of the sub? Thanks much.