This from Popular Mechanics, July 2008: Their SUVs and crossovers, the five-seater ML-Class, the seven-passenger GL-Class and the six-seater (with an option for seven) R-Class, now get the option of a 50-state-legal diesel engine: the 320 CDI Bluetec.

This car came from Florida (with 8,000 miles on it) and did not have the Bluetec option, but it's still very touchy emissions-wise.

But, I appreciate all the information and will be looking into what's up.