hmmm.. i'm sure you had the pads changed at least once. was the wear on them even or was it at an angle?

if at an angle, i think you have excessive flex in your guide bolt bushings... that is, the rubber bushing that the 7mm bolts hold the caliper to the carrier are flexing to much... giving you a vibration under braking and uneven pad wear cuz they aren't stiff enough to hold the caliper flat/still.