I drilled my own and fashioned some spacers from the foam backing it was wrapped in bring the eyes flush. They work great overall, sometimes they scream with heavy rain drops sitting on them, but once you get going they're fine and quiet. The 10-13' bumper doesn't come drilled. Buy a quality Milwaukee unibit, the steel will snap a cheap one. Measure the distance between the sensor eyes and then get them spaced right, and adjusted vertically right, then drill the bumper. As for the bumper cover cutting, a dry erase marker wipes right off and you can makes marks and adjust on the fly as needed. I used a dremel, cordless jigsaw, and various files and rasps to clean up the edges before adding the trim.