I just bought a new envoy and I am looking to get a new stereo system. I would keep the bose system but it just isn't enough for me. I plan on getting new door speakers, sub, and a new head unit (preferrably Avic Z3). I was just wondering what all I would need to hook all of this up. Would I need to rewire the door speakers? There are just a lot of little questions that I know will be involved once I get into the installation process. I just want to know what I am getting myself into before I start installing. Any info. and advice will be greatly appreciated.