My dealer contracted out CodeAlarm to install one. It was done on the dealer site but not by the dealer's employees. I want to say it cost $300. Maybe it's a bit expensive but I wanted to go through someone I knew had worked on Chargers before.
I am REALLY considering having this installed. I spoke with the dealer and they quoted me $400.00 (4 hour install) for the install alone. Not to mention the parts themselves, which totalled about $320.00 (Dealer price). So if I was to do it through my dealer it would cost me upwards of $750.00!
I investigated into this a little more and found that there is a seller on ebay who offers the OEM kit for about $270 shipped. As for the install, I asked my local, well known audio installer and I was quoted $100. So as you can see, $370.00 is a huge difference from $750.
IMO, DON'T GO WITH THE DEALER!!! I hope this helps you. Good luck!