As for the combi, I'm glad to hear it. Personally I wouldn't spend that much cheddar on something I have heard bad reviews on at all.
EPA standards drive emissions compliance, it doesnt drive the ridiculous HP and torque battles for the big three. Doesn't drive NVH ETC. Saying the engine redesigns are soley driven by EPA compliance is not accurate and leaving out a crapload of other things.
I didn't say "solely" or even imply singularity of causation. I said when EPA standards change, new engines get designed to meet them. Operative term there is when.
That's why we get new diesel engines in light trucks every time EPA standards change: the engines are designed to those standards and it's cheaper to design a new engine each time than redesign an old one to new standards.