[yesthatsteve]

I've still got 2.5 years and 50k miles on the Buick powertrain warranty (and 4.5 years/80k on the eAssist components), but I'll be open to more things as those warranty periods draw to a close. It's already got belly pans from the factory, and I live in a state that mandates E10 for everything below 91 octane. For easy gains in the short term, I'm considering a lower front air dam and taller, narrower tires (stock size is 235/50 on a 17" rim). It's been over 10 years since I had an automatic as a daily driver, so I'm sure I've still got plenty to learn.

For the OP, I did a little more digging on the '09 Malibu. According to thecarconnection.com, the 4-cyl six speed comes with a sixth gear ratio of 0.75 and a 2.77 final drive, while the hybrid has a fourth gear ratio of 0.68 with a 3.05 final drive. That puts them within a whisker of each other on the highway, with the electric assist likely accounting for the slight difference in EPA hwy rating.

My LaCrosse weighs over 400 lbs more than the '09 Malibu, so the electric assist may have greater impact at lower speeds than it does for me.