Hi guys, sorry if i sound like a moron at this but audio work is not something i claim to be up on. I have a 2012 Charger RT with the 6 speaker Alpine system. I want to change all the speakers, my question is i know there is a 3rd speaker thats unused in the dash, does anyone know if Dodge has wires in there for it though? Could i buy a 3rd 3.5 inch speaker and just plug it in and it works? Also, in the rear shelf, i can feel a space for what i assume would be a sub and there are 2 wires there that i can feel. Do those go to that would be sub? Again could i buy an 8" (I believe thats the size) sub and just plug it it and it works or is there more to this? Thanks for your help!