Keeper... this subject has received a lot of chatter... it is not a simple install, but then the dealer has no good options.
You can do it. Apparently the only hard part is getting the wires from the front to the back of the car, in a civilized manner.
Go to this page...http://www.xoutpost.com/ and read articles 18/19 (or is it 17/18?) in the miscellaneous section.

Just download and read the PDF's... should give you some helpful information.