I ordered my car with the MMI nav non-bose and I want to upgrade the speakers and add Amps. What kind of outputs does the MMI have? Will this be easy to do? Do i just take the exisiting lines to the speakers and run them to amps instead? I don't have my car yet, so i don't know what the back of the unit looks like, but i want to start buying parts so i can install soon after I get my car. Its a 2006 a4 sedan. Also do you guys know what speaker sizes I should be looking for?