Hi every one. I have a Model S with the standard speaker system. Is the wiring for the premium system (additional speakers) already installed in all cars and its just a matter of using the wiring? Is it possible to change the current speaker system to a premium system i.e. more speakers, sub woofer and software upgrade to allow for dolby? I was just wondering if the above is possible to do as a retro fit? Thanks to everyone with a response in advance.