Not always the case.
Comparing real semi's to 'road' semi's like KU36's is more about construction than tyre compound.
I reckon the 36's are about as soft as my advan AO50's and bridgestone RE55's (real semis), but if I was doing track work the KU36 would be destroyed and the AO50 or RE55 would be only half as worn. It all comes down to heat really.
DRFT31 - Depends how often you wanna replace tyres really. KU36's will wear a lot more. How deep are your pockets?
My opinion - 200rwkw's go the 31's. They're 265's afterall, how much grip do you need?
Try Traction tyres, or option 1, or OTR motorsport for prices.