I'd actually prefer the urea motor over the pre-DEF ones. The ones without DEF have to have their tuning screwed with so much to make the emissions regulations that they get poor fuel economy as a result. The DEF motors do better because they can adjust the tuning for better economy and still meet emissions standards. DEF is pretty cheap if you buy it at the right places.
That makes little sense.
Its the DPF that kills fuel economy, not DEF.
A diesel can have a DPF and no DEF but not the other way around.
