Just bought a new st. Got a great deal and couldn't refuse. So happy with it. Accessories are already being added but I am a huge music fan and without losing the 6 stacker head deck and bluetooth I wanted to get the alpine sub from my old car and connect it to the d40. I know some other manufactures have a feature to be able to plug a sub into the head deck. Does anyone know if the new 6 stacker has this or there is a way. Would love to get some more bass even though the stock speakers kick anyway.