I want to install a Navigation unit in a 2011 Cadillac STS that did not come with a navigation originally. I have already purchased and installed a brand new Denso Navigation unit that I purchased on eBay. I have also ordered a navigation DVD for the maps to work. My question is: does the 2011 Cadillac STS (non-nav) come with hookups for a microphone (Bluetooth phone) and navigation antenna, and if not, where do you install them (does it require drilling/wiring)? Note: The vehicle is already equipped with: OnStar, Sirius XM satellite radio. Does this mean I already have the GPS/nav antenna and/or microphone?