http://www.directed.com/Products/MobileAudio/HDRadio.aspx
You have two choices for connection, FM Modulation or RCAs. I opted for the RCAs being run into the Mighty McIntosh AUX In jacks.
There were 3 wires to run. 12VS, 12V+ and ground. Outside that it was running antenna wires, RCA cable and hooking up the screen.
Use of the unit is not hard, its easy to navigate. Just note your NOT on an HD channel until it says HD behind the stations addy, such as 92.5HD. If they have HD2 available, then the first channel you come across is labeled HD1. If no second channel is offered, just HD
Sound is another thing. HD touts CD quality, I dont believe this is the case. I think it lacks in depth and highs to be true CD quality. However, as long as it remains in HD mode there is no static, flutter, pop, fading or any other type of distortion or noises. The real problem with these issues is when the HD signal becomes to weak. Then it reverts back to regular FM. I believe the unit ha s a 10 second time when this happens. HD looses, it has 10 seconds before going back to plain FM.
Next issue is with your HU tuner. If you decide to use it over the HD tuner, make sure the HD is OFF. Otherwise you can expect popping, distortion and a weak signal on any band,
All in all at this point I am very happy about this purchase.