Three turbos don't make any sense on a 6 cylinder, especially a V6. Besides, they're trying to make the engine simpler and lighter. The only arrangement I see improving throttle response is a sequential twin-turbo. Variable vane single turbos for half the cylinders each (like BMW is using now) might seem comparable, but with half the exhaust volume, throttle response is half as good as with all exhaust volume going thru sequential turbos. Not a turbo fan at all, but would like to read the experts' comments on that issue
.