Newer tech meaning higher compression, better piston design, improved turbulence and flow, etc. Not necessarily something fancy like VVT , newer alloys, better coatings...there's a ton of tricks engine builders have learned over the last 25 years that are easy to implement.

Such is true, but really only because there aren't many companies in the US touting cheap diesel cars. And the latest attempt at a cheap diesel (the Cruze diesel) sucked so horribly because it wasn't really any more efficient than the existing petrol model.

More people will buy the gasoline version. For the last several years, diesel in the US has, on average, been more expensive than gasoline.

Good point. I bet it was easier for them to replicate a common gas engine than a diesel. Although I wouldn't be surprised if their next model used a diesel mill, either turbocharged or N/A.

Pretty sure this was a Suzuki motor in a Suzuki car that GM rebadged, not a GM design.

This new motor was developed by Germany's IAV and uses a different cylinder block, cylinder heads, CAM cover, front cover, oil pan, crankshaft, camshaft, valve train, pistons, connecting rods, bearings and water pump than the Metro's engine.

I bet if they used a diesel, their silly MPG number would be easy as PI to achieve...But instead, they copied and improved the Metro's engine? So, engineering on Hard Mode?

You mean other than the fact that it starts at more than twice the (projected) price of the Elio, and gets less than half the (projected) MPG?