Porsche TSs CR brakes do the same thing.I guess as expected,as they are both made by Brembo SGL...I checked the brake calibrators and discs today and all looks tight and good.Like I said,as long as the car stops as designed,I am not worried about a little vibration.I mean,their is a hell of a lot of real loud noise right behind my head that i love to hear and I and no body complains about that or that cool popping thing...