As you'd expect the middle child is powered by the same 2.9-liter twin-turbo V6 as a normal Cayenne. Unlike the previous generation, which had a Porsche-developed 3.6-liter V6, this feature a unit shared and co-developed with Audi.
You may know it from the RS4/5. However, the output has been lowered slightly to 440 HP (-10 HP) and 550 Nm (-50Nm) of torque. Porsche Cars North America rates this at 0 to 60mph in 4.7 seconds or 4.6 with the Lightweight Sport Package, while top speed is 264 km/h (164 mph). As you'd expect, this puts it right between the other two models.
Now, even though the Cayenne has been available since 2017, Porsche doesn't have that many engines lined up. The only one missing from the Couse is the E-Hybrid. But they did promise a Turbo S E-Hybrid will be developed, and a V8-powered GTS seems inevitable too.
Porsche USA also says that the S Coupe is differently equipped from the normal model, in that it comes pre-fitted with the Sport Chrono Package, eight-way sport seats, a panoramic fixed glass roof, and 20-inch wheels. All this comes in at $88,600 excluding $1,250 for delivery, processing, and handling. The standard 2+2 setup can be switched out for a rear bench.
For the record, a "normal" Cayenne S starts from $82,900, while the Cayenne Coupe goes for $75,300. Meanwhile, a Turbo Coupe will set you back $130,100. It seems that adaptive rear spoiler is expensive to make.