I installed one about three months ago! The installation instructions are pretty straightforward from the manufacture. Be careful with you chrome while doing the installation, as you will be moving from side to side while installing this item.
I'd recommend you purchase the following, a trailer harness, if your going to trailer, also I wired up at the same time the led LED License Plater Holder by Show Chrome, also installed the EC wire harness for it. The harness makes for a clean and easy install. You’ll have to drill a hole in rear fender if you do not have one now, just behind license plate. Add a rubber grommet for the harness to go through the fender. Purchase from a local auto parts store or Radio Shack, Snap Connectors, so you can just plug & unplug the Plate easily without having to cut & recrimp wires. This whole setup really looks good on the bike. I get a lot of comments from non-Wingers about both the rear lighting and the nice looking hitch setup!