Thank you for the replies so far. I have been doing some research in the last few weeks and yes, it looks "on paper" that the 390 is a 350 with TPM and a curvy road routing feature.
However, I would like to get some feedback from people who actually own the unit. Many people are fast to provide feedback when something doesn't work as they were hoping for. I don't see that many posts from people stating that something does work.
Thank you again,