I am seriously thinking of trading in my gorgeous #9 2004 prius because of having it vandalized twice right outside my house for my HID lights. This ime, several thousand $$ of damage was caused. I'm going to go down to a package without the HID's, but that means I lose the NAV. Does anyone know whether I can buy either the NAV as an optional after market extra or whether I an buy a different brand and have it hooked up to the existing screen?