the quad v6 is said to be specific to alfa, however when compared side by side with the 3.8L the QP GTS has....https://europe.autonews.com/article/20150408/ANE/150409864/new-alfa-romeo-engines-will-be-built-in-italy
Maserati will be getting 480 hp twin-turbo V6 for Quattroporte (base) and Ghibli from Alfa Romeo. Alfa has a very extensive history in racing, rally and very good engine building. A 500+ HP engine may need to developed through joint Alfa-Maserati efforts.
the v6 looks an awful lot like the v8 down two cylinders.