rubbish
I run ebc yellowstuff(used reds also), I take the anti rattle shim OFF the rear of ALL pads fitted to my cars, I have never hand on heart ever heard so much as a peep in over 25 years.
I do NOT use any copperslip or similar, just the pad minus the rear cushy pad.
It may be more a design issue with the caliper, squeal can only be caused by vibration, it the pad is physically loose enough to vibrate too much, all pads vibrate but usually at a frequency that doesn't cause this.
I have brand new 15 mile old DS2500 pads with my bubble gum pink tarox 6 pots, but won't be using them, even though I get them free, I have bought for £75 yellows to go in, as having been a user of the ds ranges before they're crap imo with zero feel needing warm up, and when being warm not that good compared with yellows, maybe one reason why over 85% of police response cars use yellows ?, or maybe it was because the ds range etc didn't get approved after extensive police mira testing ?
tabetha