I am planning on getting a Pioneer AVH-P6800. I wanted to know if I need to get the Satellite Radio tuner since I have the stock Satellite Radio. Also, are there any harnesses that i need to get to install the HU and where would I get it from? And lastly, i am trying to figure out how hard the install is. i checked some of the other DIY's, but just trying to find out what other people think.