It's the actual frame horn itself that has to be moved. They need to be cut off and welded back on lower. I moved mine 1 1/4" because I wanted a tight bumper gap. There are also some brackets that go from the frame to the corners of the bumper that have to be modified as well. Also there is a lip on the bottom of the core support that needs a little trimming.
Also here's a tip: you'll either have to shorten/buy shorter bolts for the top of the bumper, or drill a hole in the top of the frame for the bolt to pass through. Since the horns are moved the top bolts are now too long and will contact the frame.