Many studies have been launched to determine whether it is possible to achieve 0.4 gms/mile Nox. Most of those studies question or deny the ability to design and develop a system to reliably maintain 0.4 gms/mile Nox. This paper reviews the factors requiring consideration towards accomplishing that Nox objective and theoritizes a system which should properly accommodate these considerations. Actual performance data is then presented on a commercially manufacturable system that demonstrates conformance to the 0.4 Nox requirement without penalty to economy or driveability. Finally, considerations toward even superior performance are presented.