I have a problem with a vibration (NOT GOOD VIBRATIONS) when I am braking as the car is between 40 and 45 MPH. If I brake harder or if my speed is above or below these speeds, I don't get this. I had this problem before my last brake job and alignment (15-20k ago) and it went away for a short time. I'm thinking that it may be due to the rotors? If so, should I just resurface again and have this problem return or should I go with slotted? Any other ideas? Thanks. PS Great info on this site!!