That's VW's word for it, not
That's VW's word for it, not mine. Notice that back in 06, the development manager had opted for the catalyst treatment. However, once the manager was bumped out of his lead position and the EA189 became solely an in-house project, the usual VW mindset that says "if it's not invented here (meaning Wolfsburg) it's no good." Believe it or not, they tried super lean-burn technology that has been tried and dropped by more than one automaker.