We shall see, if the costs come down on a Twin Charger system, how many production cars will have it in the future. American Auto makers usually prefer Superchargers. Japanese, turbo chargers and Europe.. well it looks like they may prefer both turbo charged and supercharged.
Interestingly enough Volkswagen intially developed this to get better fuel economy not power from its engines. Of course as a result you'll get better HP too which is nice. Someone has told me they have had this system on Big Rig trucks for years but not passenger vehicles.