The S8 Plus will be replaced by the plug-in hybrid E-Tron.

The all-new Audi A8 has finally arrived. There are already some hot rumors about the other members of the family. The dynamic S8 and S8 Plus are the ones we’re referring to. They will continue to be powered by a biturbo-4.0-liter V8 engine. But there’s a twist. The engine will not be Audi’s as the full-size sport sedans will use a Porsche unit from the Panamera.

The S8 engine will have a slightly different tuning as it doesn’t have the Panamera’s full 550 horsepower. EVO says that the engine’s output will decrease by about a dozen ponies. There is no word yet on the torque, but it seems safe to assume that it will be lower than the 567 pound-feet (770 Newton meters) of the Panamera Turbo.

The all-new Audi S8 will take around four seconds for the 0-62mph (0-100 kmph) task, en route to a top speed greater than 185 mph (298 Kph).

The Plus model will offer a faster S8. A name change might be necessary as another report suggests that Audi may sell the S8 E-Tron as an S8 E.Tron, to signify it will feature a plug-in hybrid arrangement.

It is possible that the hardware will be borrowed from the Panamera Turbo S EHybrid. Power? The Porsche has 680 horsepower and 626 lb-ft (850Nm) respectively. The S8 E-Tron will be slightly lower, but still sufficient to deliver some amazing performances for a car this small: sub-4s in the sprint and a top speed of 190 mph (305 km/h).

It’s hard to imagine anything else that could top it, so at the very least, it seems unlikely Audi will release an RS8. The S8 E-Tron should satisfy 99% of those who are looking in this segment. Porsche confirmed that the next generation Cayenne will feature the same powerful powertrain.

Logic says the S8 will be released first, possibly in 2018. The range-topping S8 Plus / E-Tron will follow at a later time.