Rumor gets stronger and stronger: x55 engine seems to be replaced by a normally aspirated 6.0 l V12 engine with 500 HP or slightly more. Torque is rumored to be in the 700-750 Nm range. To me it sounds strange that the supercharged V8 will be replaced by a V12 (even if normally aspirated) but everything is possible. Personally I still put my bet on two other variants: supercharged V8 4-valve engine with direct fuel injection or a twin-turbo(!) charged V8 4-valve engine with direct fuel injection, both delivering around 520-560 HP.
The next two years will be interesting.