Greetings,
I replaced my pads last month with Hawks HPS without OEM shim. So far, I haven't heard any squealing. Although I did applied some MOLY anti seize paste. At first, I was going to reuse the OEM shims. But upon inspection of the HPS pads, they appeared to already have shims attached to them from factory. Just in case though, I saved the OEM shims for re-attachment if necessary. Hope this helps.