Ah, you're the one...I remember reading about that...NICE JOB! Yeah I was aware of the hardness scale and had researched it before I bought the Whiteline bushings. Usually when you hear people talk about differential whine it's more gear alignment or something of that nature so I wanted to make sure you weren't trying to compensate for that.
I'm going to do the differential bushings as well when I do my LSD, but I had planned on the whiteline...I don't want any aluminum bushings, that's not a bushing, that's a thick washer