Is the only difference between the nav and non-nav Camry Hybrids strictly the Navigation unit or are there other small "benefits" that come with the unit. I t I read a thread where there was additional mileage info if you got the Nav system?

For example, the Civic Hybrid also comes with a Digital Audio-Card reader.

Trying to decide if I want that Nav system since I already use a Garmin that I upgrade regularly anyway.