The worst heat is radiating from exhaust headers. If you e.g. look at carbon heat shields (those without aluminum inner heat shields) you can usually see burnt carbon where the shield is closest to headers and around mounting points. Melted right side bottom firing is also quite normal (where the headers are close to firing). I have also seen burnt carbon rear fenders (usually happened during dyno times) at points closest to rear header. But I have never seen e.g. a burnt rear Cylinder Head “Carbon” heat shield. Peoples removing rear CH heat shields usually says that they do not feel any difference after removing it… Just my thoughts.