I just picked my A5 up a week ago and changed all my settings in my U.S. spec A5 to kilometers in the "car" settings without VAG COM, for the purpose of showing km/h in my display. However either I've changed the wrong setting, or the software is off in the car because it shows me doing 40km/h when I'm over 60mph. I'll play with it more tonight and tell you, I've still yet to figure out all the settings as I lack attention span with all the cool buttons and lights in the car.
You can change the digital speed reading and the mileage units. (Plus temperature from C to F if you want).
I took my car to Belgium over the new year and did the switch as I was waiting to get on the boat.
It's under CAR > SETTINGS and then I think it's under UNITS.
You also have the opportunity to change the pressure from bar to psi, but I don't for the life of me know where that readout is or why (tire pressure perhaps?)