1999 2.5L 5-speed

Typical 21-22mpg. High 24, low 19. Drive it like I stole it on 91 octane Commiefornia Premium Unleaded with 10% Ethanol.

My combined city and mountain driving nets 26 - 28.6 MPG. It doesn't matter if I'm kickin' it in the mountains at 90+ or keeping it "legit" around 65-75. Great car with great mileage.

I've checked the mileage on my 03 Boxster S several times and always am right around 27 mpg, virtually all highway driving since I live in the country. Doesn't seem to matter that much if I drive it like I stole it, or just putt around, always right near 27 mpg.

According to the car, I get 18.7. That is the average over the last few months.

I haven't done the calculations myself.