Not sure if it really adds navigation but what it does is basically hacking the existing entertainment system and unlocking the navigation system that might be there.
In other words, it can't add what doesn't already exist in the factory unit.
What vehicle manufacturers often do now days is use the same entertainment system for all trim levels, but lower trim levels or they do not enable some premium features in order to entice one to buy a higher trim level.
So, for this to work, there will be some very specific requirements, For example, the Ford version of genie requires a specific entertainment system with 8" screen in very specific model yrs with a specific firmware version..
There is a chance on lower trim levels that the entertainment unit may not have GPS capability (no hidden setting to hack and no GPS sat receiver) so pay close attention to all of the requirements spelled out by genie before ordering..
If the vehicle manufacturer does a forced firmware upgrade down the road, the hack may cease to function and then you would have to go back to genie to make it right.
You are taking some risks that the hack may brick your factory entertainment system.
For the $500 genie wants for their "product" and the fact you are basically hacking your factory radio I think buying a aftermarket GPS might be a better route..