so ive looked int o the raio a little bit and i have found a double din unit with a storage for a regular head unit. i have a as3 soundsystem. what will i need to do to make sure that the subs on the rear deck and amp work with the new headunit. the new headunit has 2 sub auxillary output and has full bass control levels but im pretty sure those inputs are for aftermarket subs. what wires do i need to use to do this very confused. i drive a 2001 saab 9-5 all help will be greatly appreciated thank you.