I bought these as an upgrade to my stock rotors for my 2014 Mustang GT. I didn't install them for a few months after ordering. After I installed them I experienced a great deal of modulation while braking. Braking was not smooth at all. Because I waited so long to install and did not have any of the original packaging I did not try to return them. I did order different rotors and braking is back to being very smooth.
Nice pads/rotors, so far
They look nice. I put the sport rotor and yellow pads on my yukon 4wd for fun. The existing brakes worked fine, but I wanted to mix things up a little. Not hard to install (no clips though). The first 2 miles.... grinding, crunching, squealing, but then the black finish was suddenly gone and they sounded smooth. You can hear the windy-sound of them. They work as good as the originals, but I have not tested them (the instructions call for a 1000 mile break-in period. What's that all about?)