Im new to hodas world and ive been looking for honda civic gen 8 hatchback but there are some things i can not undarstand. First what are the diferences betwen the sta nav and original radio exept the navigation is the speakers wattege output is higher or not. So i want someone to tell me what wattage is the sat nav,the normal and the premium. Because the only thing i was abble to find is that the premium has only a added sub with amp for itself, is that so? Also is there a diferent speakers or they are the same/or there are 2 more? Also i want to knоw where the sub is located so i can look for it when I look for a car? And last is there way to upgrage an non premium sound sistem to a premium- adding an original sub with its amp?