When the Falken 615s came out they owned the street tire (non racing slick) class in autocross for several years. Other manufacturers finally matched them, but the 660s are currently very competitive in autocross where maximum grip (not heat resistance) is paramount.
Grassrootsmotorsports does multiple tire tests per year (whenever a promising tire is released) and the Falkens are near the top of their testing. I don't remember them testing the PS4S and certainly not the TPC ones.
My guess is the Falkens would overheat on a 4200lb car on a fast racetrack in short order (fast autocross tires often get cooled with water after a 60 second lap to maintain their grip), but I do think they might be promising for regular street driving.
I'm sure the Cadillac engineers choose the best tire available for a wide range of requirements (low noise, great ride, ability to do track days for multiple hours, good wet and dry grip, etc), but if your only requirement is dry grip I do wonder if the Falkens would be better.
Someone in Florida (where Grassrootsmotorsports is based) should volunteer their blackwing for a tire test