Our 31E has a "higher end" axxera with a "sub navigation" the system seems to switch AV over to it. played with it a little and wasn't impressed. during a 4 digit amazon shopping spree, i bought a Garmin 770 despite the bad reviews. personally i think the reviews come from mis-programming the unit. i figure i can always download an app or use google maps on my phone if the Garmin fails me.