[Mike Simard]

Chas, I've been eliminating brake squeal too and have tried different Wilwood pads. Wilwood has about 10 pad grades. Most are high temp race pads but there are 3 lower temp grades that could work on the street. I started with the "T" grade that came with a Dynalite kit. They are cold stoppers that are very quite, stop well cold and fade badly on the track. Next up I tried the "E" grade which have a fairly high temp range for a 'streetable' pad. They squealed horribly loud and were probably eating the rotors. I tried machining the metal backing flat and lubricating the pad-piston contact area but nothing got all the squeak out. Now I have the "Q" grade, they are in between the T and Q for temp and are dead quite on my car, they are machined flat and have lubricant but no shims. I'm finally happy but do plan to swap pads for the track. I wonder what Wilwood grade your Sierra pads are equivalant to? BTW, I did try shims briefly but felt that the pedal was a bit softer. Lubricating the pad-piston contact seems to be very effective, I used some gooey engine assembly lube because it was handy. BTW2, you were making stops from 130? You can heat a pad up hot enough to warp the metal backing, I've done it. If that surface isn't flat to the piston they could be like vocal chords.
edit: changed first reference of "E", did say Q, Doh!