Well, if BMW can put a 4 cylinder in a 5 series weighing over 4 Grand yet provide the similar torque and HP then you see where the CAFE standards are leading us. I bought the last 6 cylinder 5 series in 2011. Smaller, 4 cylinder diesels will likely be the norm and watch for Ford 150s to arrive WITHOUT a V8 pretty soon. But, heavy Rvs need TORQUE first then HP and gearing and the Sprinters with 5sp/6 cyl turbos have done well hauling 11,000 pls lbs. I say, caveat emptor --don't be intimidated by advertising smokescreens. If possible...!!