I will be installing an amplifier and subwoofer in an '04 530i (E60). I choose an amplifier w/ high level input so I don't need a LOC. I am under the impression the battery is located in the trunk so that should be a breeze. I also read there is a amplifier in the trunk already and I can tap into that connector for signal and remote turn on. Does anyone know what wire colors I should hit to save time probing? Also anyone know if any problems I will encounter? All tips are greatly appreciated & thx in advance.