Review on StopTech 126 34093SR Sport Slotted Brake by Sean Reddy

In 2015 I bought two sets of these StopTech discs for two of my 2008 BMW 335xi. The first set was perfect, both on the road and on the track. The second sentence is NOT. After installing the 2nd set, this car immediately had strong vibrations when braking. So bad that I thought maybe something was assembled incorrectly and was therefore disassembled/reassembled; no improvement. While the vibrations improved over time, especially after a session at the track, they never completely went away. So everything was disassembled again, even the guide pins replaced, the brackets smoothed and lubricated where the pads "float". No improvement. I took the car to the dealer and they said the rotors were deformed. While I know "warped rotors" is not a definitive diagnosis at all, I replaced both rotors and all is well again. In my opinion there is no quality control on the rotors of this brand and I will not buy them again.