We have had this discussion on the truck side of things for a couple years now. My 2006 5.9L Cummins was getting 20 USmpg before the mods. My dads 2008, with the 6.7L and all the emissions crap was getting 16 US mpg. Same general technology (common rail, except the 6.7L uses higher pressure), same body design yada yada. He pulled the DPF, NOX catalyst, and cat convertor off, and now gets upwards of 22-23 usmpg....mostly a result of freeing up the breathing of the engine. In theory the 2.0L should return the same or better mileage than the 1.9L, but due to the emmisions crap, wil return lower mileage on average. Take that stuff of, and it should be higher than the 1.9L based on the more efficient fuel system.
2006 Jetta 5M, stock for now