Hello everyone. My car currently has a symphony headunit and BOSE factory fitted speakers, with rear amplifier, i want to replace the headunit for my alpine ipod unit. does anyone know if i need more than simply an iso adaptor in order for all the speakers to work? i am told i will only be able to get the fronts to work as they are amped off the headunit? will i be able to get the rear amp working or should i be looking to replace that as well? thanks, Joe