With the days of super-cheap gas long behind us, the four-cylinder engine is rapidly becoming “king of the road.” Many of them are now as quiet and powerful as V6 engines used to be, and they’re showing up in more models than ever.

Saturn has responded with the midsize Aura sedan. The 2.4-litre four-cylinder previously found only in the base XE model is now also available in the upper-line XR trim. GM further streamlines the model by dropping one of the two V6 engines offered for 2008; for 2009, there’s only a 3.6-litre V6, solely in XR trim. The 2.4-litre also shows up in the Aura Hybrid, a “mild” version that shuts off at idle, but can’t run on its battery alone.

Mated exclusively to a six-speed automatic — sister car Chevrolet Malibu uses a four-speed in its base trim — the 2.4-litre Aura gets better overall fuel economy than any of its non-hybrid, auto-equipped midsize sedan competitors. Official figures are 9.4 L/100 km in the city and 5.9 on the highway; in combined cold-weather driving, I averaged 8.9 L/100 km.

Pricing starts at $23,728 for the XE, while the XR-4 starts at $26,395. Features on the upper line include auto-dimming mirrors, 17-inch alloy wheels, heated cloth seats (optioned to leather on my car, and which took forever to warm up on my tester) with power adjustment, remote start, Bluetooth and satellite radio. It’s another $4,111 to the V6 model, which also adds 18-inch wheels, leather upholstery and automatic climate control. Electronic stability control, six airbags and OnStar are standard on all models.

Drive-wise, I’ve always been partial to Aura/Malibu. It isn’t that anything really stands out, but it’s a cohesive package that does what it’s meant to do, and does it very well. The 169-horsepower four has enough guts to get through traffic; the interior is roomy; the seats are supportive; the suspension takes care of nasty road imperfections; and fit-and-finish stands up easily to its rivals.

The steering’s a bit livelier than on sister Malibu, but it’s still no sports sedan. Its light feel will displease driving enthusiasts, but the reality is that this car is aimed at commuters, and that’s what most want when they’re snaking through city streets en route to the office. It’s responsive, though, with no wallowing or rolling around corners, and it’s straight and confident on the highway, with no need for constant correction.

Overall, controls are simple and easy to use, save for a fiddly power mirror switch that isn’t backlit at night. I also wish GM would find a new steering wheel designer, as it’s got just about the ugliest ones in the industry.

It’s a crowded market, but GM has delivered a top-notch contender, sweetening it by mixing upper-line trim with a smaller engine. There’s no reason why you can’t be frugal and extravagant all at the same time.