– Detroit, Michigan

As much as I wish I could spend every morning at the helm of a Ford Mustang GT350 or a Porsche Boxster, traffic and stoplights don’t always allow me to actually exercise the cars’ potential. My 18-mile daily slog through traffic takes about 35 minutes, so it really doesn’t matter how much horsepower I have available. In fact, I could probably manage fine with just three cylinders. And I did.

As almost every automaker works to downsize every engine possible, Ford now offers a turbocharged 1.0-liter inline-three engine as an option in the Focus (as well as the smaller, lighter Fiesta). Though it’s less powerful than the Focus’s standard 2.0-liter engine (by 37 horsepower and 21 pound-feet of torque), it’s also considerably more fuel efficient, at 30 miles per gallon city and 42 mpg highway. Opting for the 1.0-liter engine on a Focus SE costs just $495, so the payback period is relatively quick compared to, say, buying an expensive hybrid. The main question is whether buyers are willing to sacrifice power in exchange for a little bit more efficiency.

Pros

• Performance is impressive given the engine’s small displacement. Yes, the car is slow, but the broad torque delivery makes it easy to keep up with traffic, so long as you shift the six-speed manual regularly (a six-speed automatic is optional). Engineering tricks like an intentionally unbalanced flywheel quell vibrations, so whether it’s idling or running toward its 6,500-rpm rev limit, the three-cylinder i...