Bummer on the lack of Passat wagons. I was hoping for that to be my wife's next car.

I think there is a lack of clarity on the function of DEF or the extra Diesel fuel for NoX adsorber regeneration. Essentially, they do the exact same thing. Adsorbers hold the NoX on the surface of the adsorber and have to periodically be cleaned off so there's room to grab more NoX. Either system just raises the temp of the adsorber medium and kicks off the catalytic reaction, turning the NoX into N2 and O2, which quickly turns into H2O when combined with atmospheric H2. So it really doesn't matter which system - you're either buying DEF or a little more Diesel. BTW - the FE hit for the Diesel fuel system (at least on heavy duty Diesels) is about 2% and that's from repeatable lab testing.

I'm not sure about current technology but in years past the European versions required a trip to the dealer for regeneration every so many miles (not sure of the interval) instead of the on-board regeneration system. In the US it was decided that that was unacceptable as we can't even get people to check their oil so how the heck can we expect them bring the car back for service of the NoX adsorber? Sad but true.

Dan