RC:
The Cayenne 6 cyl. engine is from Volkswagen, the V6 for the Panamera from Porsche.
Which one is better? Well...I actually would put my money on the Porsche V6, especially since it also delivers more power.
...used to be the case for pre-2011 Cayenne V6. Starting 2011 Cayenne V6 engine is not VW, but Porsche V6 (the same V6 engine, used in 6cyl Panamera).
Actually, it's a Cayenne S/Panamera S V8 "minus two cylinders". That's how they implemented this Porsche V6 engine...just by modifying V8 engine by cutting 2 cylinders.
...regarding the orig post topic,..
This tendency to substitute V8 with the turboV6 is a new efficiency "fashion style" in many German car manufacturers. The new BMW M3 will have V6turbo instead of V8. All new 3series BMW cars are coming with the v4turbos instead of V6s, as it used to be.
German car manufacturers started to "cheat the customer" into an idea of getting even more fuel efficient car w turbo engine and "2cyl less", than regular nonturbo engine, advertising same or even little increased hp with the next generation turbo engine. Advertising a better gas efficiency for the same or higher priced "less" car. They started to "downgrade" engines: V8 into V6turbo, V6 into V4turbo. Very soon this path will lead us into well developed Japanese V4turbo cars and 2cyl motorbikes territory.
While it may be suitable for compact low weight little cars/little low weight sport cars, it's a path into disaster for big heavy sedans and SUVs (Panamera V8, Cayenne V8).
...it's the beginning of the END of a Porsche sedan/suv...a full VW Audi economic corporate mentality takeover and absorption.
If they put this V6turbo into next Panamera S/Panamera GTS (which they probably will), they WILL definitely put this into CayenneS/CayenneGTS too.
I can't imagine a disaster next CayenneV6turbo instead of CayenneV8... ...even worse, than PanameraV6turbo instead of PanameraV8 substitution...
Imagine MacanV6, PanameraV6turbo, CayenneV6turbo, PanameraGTSV6turbo, CayenneGTSV6turbo...They will share the same base V6 engine block vs "preserved" current TURBO Panamera/Cayenne models with the V8 engine.
But they will keep prices advancing higher...
If you want to get into SUCH future sooner, start buying Japanese 4cylturbo compacts (SubaruWRXs, MitsuEVOs and etc) INSTEAD of PORSCHE Panamera/Cayenne...
This is a path into disaster, into NOWHERE - into THE END...