I got some interesting info from the Vienna Motor Symposium 2017.
Here in Europe Mercedes will offer the new 3.0 I6 engine with 2 power levels.
S400 - 361hp/367ps - 369lb-ft/500Nm
S500 - 428hp/435ps - 384 lb-ft/520Nm + 22ps - 184lb-ft/250Nm E-Boost, thanks to the new mild hybrid system with the ISG (Integrated Starter Generator) which reduce the turbo lag.
So the S500 will be the direct competitor to the LS500 here, and not the S560. Lexus is a real game changer now and they can steal many buyers from the german trio this time, especially from bmw and audi V6 with V8 power, RWD/AWD options and the most original design.
Interesting bit about Vienna Motor Symposium 2017 is Toyota engineers presenting something about clean diesel technology .
For those who dont know, this is premium engine-related event where many car manufacturers reveal new technologies or explain them better... Toyota has shown their estec engines, diesels, and more in past few years.