I had some sqealing pads on my 911. I sprayed the backs with some anit-squeal stuff and the squealing went away. It could be your pads. Or, it could be that they don't have a good seat with the caliper and they rattle around producing the high pitched squeal. Maybe mine no longer squeal because they fit better or the spray is damping the rattle by filling the gaps in the bad fit...? Anyway, mine are quiet after remove and reinstall with the anit-squeal spray. Try it, you might get lucky.