I got this quote from link
2000-2006 Honda Insight - Top Speed
"At highway speeds, the airflow around a vehicle becomes turbulent. Turbulent air generates considerably more drag than smooth-flowing (laminar) air. In addition, as speed increases, the power required to overcome turbulence-induced drag rises exponentially. To combat the effects of drag, Honda engineers designed the Insight’s body to be highly aerodynamic. Its 0.25 coefficient of drag (Cd) is one of the lowest of any mass-produced automobile in the world. In comparison, the Honda Civic Hatchback, with roughly the same 1.9 square-meter frontal area as the Insight, has a Cd of 0.36, and needs around 32 percent more power to operate at the same speed as the Insight."
Holy cow, 32% more power. I know a crx isn't an insight, but the calculator suggests the insight would be 40.12% higher mpg at 60mph, the crx would have 29.53% more mpg at 60mph.
Roughly 3/4 of the gain in the insight, so maybe 3/4 of 32% is 24% more power needed to keep my 96 civic at 60mph than a crx at 60mph? That's a lot of extra power needed.