I had the Oxygen O'Car as my head unit. It is unique as the iPhone IS the head unit that you can control everything from. It had a mic you could connect, amplifier and everything worked great for voice calls and music. http://www.oxygenaudio.com/en/15-o-car-3527570040573.html It's old now and doesn't work with the iPhone 5. When the iPhone 5 came out, despite having a unique innovative product, I just read Oxygen abandoned their iPhone 5 compatible update to the O car. The ONLY other car unit I could find is this http://www.iroconline.com/iRoc/index.html but again, it's an older iphone 4 compatible only and they seem like a flakey company. It's a shame as there is a big gap in the market for one of these devices. Is there anything like this which will act as an amp and support a sub have a mic for clear voice calls (the iPhone mic and loudspeaker doesn't cut it) work with siri to pass though audio to the speakers iphone as the interface - not a 'traditional' head unit. Something like the defunct o'car Thanks for any suggestions!