I went with the ECS kit over the brakeperformance is my wife and kids ride in the X5 all the time. I wanted something I could trust. I can stop a car without brakes, I don't think my wife can. She would panic till she hit something, I woud do a controlled crash or rub a curb till it stops. It looks like brake performance buys their rotors from the same factory Centric does by the specs being the same.

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2002 X5 3.0i I work on it the wife drives it.
2007 Maxima SE my car