all in this one unit (it does so much more like lists MP3 songs by Name and allows you to put them into separate folders on an MP3 disc instead off having a list of about 120 songs to choose from you can organize by genre). It is also Sirius Satellite Radio capable; shows in-coming telephone numbers on screen if you have U-Connect set up in your vehicle.  The NAV system will either talk to you through your car speakers (automatically lowers music level so instructions can be heard clearly) or give you on screen directions; its truly a cool toy and will light up your entire car at night (if you want it to; screen brightness is adjustable). I seemed to notice a better sound quality and more power out of this head unit than the NON-NAV unit.