“FYI: Increasing percentages of new mainstream (not luxury) cars require premium gas to meet performance, emissions and fuel economy standards.”
Fair point. I haven’t been in the market lately, but I know some of the compression ratios are approaching those of diesels.
Gasoline direct injection (like diesel, only using gasoline) is a modern technology used in even econobox engines to improve performance and fuel economy while reducing emissions. You can’t get modern power numbers reliably without it, especially with turbos - and even the lowest of the low ranked cars have those now.