I am looking to purchase a second car to drive on my daily driver for work. I found two dealers that each had an A6 in stock (one 2006 and one 2007), and I like the car. However, because of the amount that I will be driving, I was looking at replacing the head unit to something that is compatible with Android Auto, such as the Pioneer AVIC-7100NEX, because I use Google Maps to get from place to place because of the traffic updates. My question has to do with the compatibility with Audi's MMI. Is it possible to replace the existing head unit with another? Also, it is my understanding that MMI is not just the multimedia interface, that it controls other parts of the vehicle as well. Is this correct? Thank you in advance!