Whats the best option for removing the rear amps

Want to loose the weight but keep some radio capability...I listen mostly to the motor But if I delete the amps out bck from the mach 460, I understand that I'll kill power to the front door speakers too...is the head unit completely un-powered or is it low powered? I just want to keep basic radio sound.
GI Joe

well I'd like to get mid range too...