A word of caution:
NAV works as it does because it stores the maps onboard.
It is rumored to be updated, so Porsche wants you to buy the annual subscription to the NAV and Infotainment package. In the year I was subscribed, there was no update.
There was probably no update in the last 5 years, if not more! My own street in Houston is shown to go through the Houston Community College campus. That segment was pedestrianized and secured with massive barriers at least 5 if not 6 years ago. NAV INSISTS that I barge through the barriers and wants me to do U-Turns to do this.
If it screws up right in front of my house, how can I trust NAV to know that a one-way street has been reversed, in an unknown city, in the middle of the night? I have no confidence in NAV.
I prefer to use Google Maps which are mostly up to the minute, I like the traffic re-routing feature as well. Ocassionally I will use Apple Maps for the Siri Voice activation, if I am driving and want to get new directions to a different place.
Google Maps requires a few touches with Voice Activation, while NAV is guaranteed to kill you if you are trying to find a place while driving and get directions to it. No voice. You can get a few voice commands in with Porsche Connect (not to be confused with Porsche Car Connect by Vodafone), but still it is miles away from true Voice Commands Navigation.