How important is it to use the 2 set screws that hold the rotors on? I just did the front pads and rotors on my teg and on both sides of the car the 2 screws that hold the rotors on were all rusted and stripped. So i had to fight like a bitch to get the rotors off and had to reassemble everything w/out the screws. I was told by a friend that you really dont need the screws. Anyone know if this is true?