These were a new install, since my car only came with one standard chrome mirror on the left hand side. I was installing sport mirrors, and needed to start over since the original holes were not the same measurement center to center. I drilled the holes, and used the install tool also sold here. They sucked up tightly to the sheet metal, and the mirrors fit solidly with the only flexibility being the movement of the sheet metal. They could even charge a little more for these, and I would still feel like I got a good deal. They're excellent, and work as they should.