I am planning to purchase an aftermarket stereo such as the SONY XAV AX-1000 stereo. The number of different adapters is bewildering. My car is an Audi A3 8P with BOSE front speakers, which I presume are active. The radio I currently have is an AUDI concert EU A3. Which is the correct adapter I need to get for this? Ideally I would also like to connect the existing microphone to the new stereo as well. The SONY stereo has RCA pre amp outputs. Can these be connected directly to the active front speakers?