Now that I've had a few days to test drive the language change, the mpg is better on the face of it. The nav is still off. I can see that it lags behind the display map and can accept that as a function of the cd based system not able to keep pace. What I also see quite clearly is that when I follow a saved route, and then deviate from the route; i.e. bypass an exit or turn it has planned, it consistently shows my car following the planned route and tells me to turn after whatever number of feet. I was on the 215 fwy headed west. I had Ontario Mills shopping center as the destination. You could stay on the 215 or exit to the 10 freeway. The next exit on either freeway will get you to this huge center. The system wanted me on the 10, I stayed on the 215. The map showed me on the 10 and told me to take the next exit, which has a completely different name than the 215 exit. That had to be an 1/8 of a mile error. It caught up with me at the exit on the 215. It also has shown me offroad when I'm on. How do you translate this to a technician so they will address the real problem? Is it software or hardware?