The 2007 Aura Green Line slots between the Aura XE and XL on price, and offers a 164 horsepower hybrid powertrain based on GM’s 2.4-liter Ecotec engine. It’s the same drivetrain that powers the Vue Green Line, which delivers 27 mph in the city and 32 on the highway. The Aura’s aerodynamics are considerably better than the Vue, but it weighs more, so we suspect fuel economy will be roughly on par with the Vue. Saturn claims it will have 25 percent better economy than the base XE. The only transmission available is a 4-speed automatic driving the front wheels.