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DAEMANO alludes to this but one of the major factors here is that Wilwood and other dedicated racing calipers don't have any harmonic dampening built in whereas any street focused caliper will. For reference, several people reported the Winmax W5s as being civilised enough for street use on an OEM caliper but in the RR SP kit, they are far too obnoxious for that.
So far, Yellowstuff is the only pad I've found that stands up to track abuse and is still quiet on the street in my SP kit. I do have complaints about them in that they don't last very long and they don't have the type of bite I'd like from a track pad but they are certainly serviceable for their purpose as a dual duty pad. I'm going to try the bluestuff down the road but not until after I've been through the other pads I've got.