As you may have heard, Mercedes-AMG is planning on creating a performance sedan along the lines of the Porsche Panamera. This is part of Mercedes-AMG's push to become more than just a tuning company. The brand wants to become more of a sports car manufacturer.
The new AMG performance sedan will be called the GT4. Here is some stuff that we know about it so far. The styling will be borrowed from the AMG GT, but the styling will be "sleeker" than a typical sedan. Mercedes-AMG hopes that this will set its sedan apart from the Panamera. Though the styling will be borrowed from the AMG GT, it will still be all unique, inside and out.
The GT4 is going to be based on the upcoming CLS platform. Because of this the engine will have to be moved back as far as possible. It also won't be able to use the aluminium spaceframe structure, like is found in the GT sports car. Suspension, steering and brakes will also be shared with the next CLS. The GT4 will have relatively compact dimensions (when compared to something like the Aston Martin Rapide), which should make it easy to get in and out, and will make it highly manoeuvrable. Still, it will be a foot longer than the AMG GT, and will be more than 4 inches taller.
Speaking of the engine, it will come from Mercedes-AMG. The GT4 will likely get the twin-turbocharged 4.0-liter V-8, and it will likely be rear-wheel drive. In its highest output, that engine should produce around 600 hp.
So when are we going to see the GT4? Probably in 2019. That is one year after the next CLS will go on sale.