According to
Do Diesel Cars And Trucks Save You Money? Not Always - Forbes, diesel vehicles generally cost more, but there are exceptions, two Mercedes luxury vehicles, "the diesel versions of the Audi A3, the BMW X5, the Ford F-350, and the Volkswagen Touareg. The other Mercedes diesels on the list are the E-Class, the M-Class and the R-Class."
They also say that new diesels are cleaner than gasoline engines. I thought that I read a recent post here stating otherwise.
I only "know" what I find when looking into ideas that I had not considered. Meanwhile, I have a budget consisting of Monopoly money.