Kobalt:

Didn't AP say something like "it is virtually the same engine as the cup"?

Do we actually know what differences there is between the two engines?

The Cup's engine needs a rebuild after 100 hours and the GT3 after 300.000 km's?

All these questions...   

There are probably some minor differences . 

Here are the technical info of the Cup 

911 GT3 Cup - Vehicle description.pdf


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 964 Carrera 4 --  997.2 C2S , -20mm --  991 GT3 RS