Both are combined with Selective Catalytic Reduction systems, which, while in principle are the same, differ in application design based on vehicle parameters and emissions targets. (greencarcongress.com)
One is its use of a selective catalytic reduction system in the exhaust, which comparable Volkswagen cars don't employ. (cars.com)
3.55 Rear Axle Ratio800 Amp Maintenance Free Battery3.0 L Diesel BadgeSelective Catalytic Reduction (Urea) Next Generation Engine Controller (carsdesk.com)