OEM is usually the way to go in most cases like this. But it can add up rather quickly, between buying the bezel, stock wiring harness, the hitch and the time it will take to install everything, especially at the dealer $$.
If i were you consider the install yourself and gather the parts off ebay, you'll save alot.
OR.... you can buy a draw-tite or curt hitch off ebay for $113 shipped and an aftermarket harness for about $25 shipped. I plan on going with a draw-tite mainly for a recovery shackel (trails) and or cargo carrier (for camping).
Just something to think about