Shokeus/ACT80 (which/who may be one and the same; I often wish "antialiasing" applied to the authors) have done three Carrera Cup cars: the 964 was geared way too long (212 mph theoretical); the 996 was geared a bit too short; and the 997 is almost perfect (about 165 mph actual). It gets around Road America only a second or two slower than GT3 cars that came ten years later (the 997 Cup races ran from 2006 to 2013). The default setup is rubbish (the TPs are waaay off), but the car responds...
Porsche 997 Carrera Cup @ Road America
Porsche 997 Carrera Cup @ Road America