No, it's not a civic, but I do run regular gas and have seen a best of 27mpg on the inner state. As odd as you find it that some people are concerned with fuel economy in a 20-year-old V8 powered sports car, I find it funny how some automatically decide that owning a sports car means you have to get ****ty mileage in order for it to be taken seriously. What's the matter with wanting and achieving both? And it's really not all about maximizing torque multiplication. If that were true, the fastest cars would be running the lowest gears and they're not. I've learned from experience that a balance needs to be struck between horsepower, actual torque output and where it occurs in the vehicle weight and torque multiplication achieved by rear end ratio. Believe it or not, my Cougar was both faster and quicker at the track with the 3.27's than it was with the 3.73's. That being said, this Mustang is mainly a pleasure cruiser....so I'm not overly concerned with running it down the track with just enough gear. At the end of the day, the majority of my driving isn't going to be spent at WOT crossing through the traps at 6,000RPM. A balance needs to be struck between best acceleration and best economy/drivability. ....and I've heard nothing yet that tells me a blanketed respnce of 3.55 or 3.73 is it?