I realize this is a pretty old thread, but I thought I would add my experience to it. My local Ford dealer wanted $150.00 to install the diffuser for me, so I decided to do it myself. MAN... am I glad I didn't pay the dealer to do it. I drilled the holes for my reverse sensors, and my son and I installed the diffuser in an hour and a half. That included taking some time to clean out the dirt and grime that had accumulated under the bumper cover while I had it all apart. It was a piece of cake! Don't be intimidated by the prospect of having to remove the tail lights and bumper cover. It was not difficult at all. The part that took the longest was measuring for the sensor placement several times before drilling them out. After that it was a breeze. I installed the GT500 rear spoiler as well. Before and after pics are attached.