There are retards on both shores of the ocean. I see plenty of cars in my neck of the woods with US license plates from all over the states and my guesstimate is that they are too broke to pay 2-3k to register their junkyard dogs in this country.

Actually the nox is produced when the mixture is too lean so they need to pump more fuel per cycle in order to get the richer A/F mixture to burn at a lower temperature