SEOUL – Chalk up another win for Kia with the ’12 Rio subcompact, one of the last models to be restyled under a product renaissance that has seen the brand transformed from cheap to chic in just 2.5 years.

Starting with the quirky Soul in 2009 through the Sorento and Sportage cross/utility vehicles in 2010 and this year’s launch of the Optima midsize sedan, Kia has been on fire.

The auto maker claims the Rio leads the segment in many categories, albeit some shared with its Hyundai sister-brand’s Accent, including class-leading horsepower and torque, fuel economy and interior quality.

The differences between the two subcompacts are more pronounced today than in the past, each with its own sheetmetal, interior styling and on-road demeanor.

The Rio has an uncluttered European look, reflecting the influence of chief designer Peter Schreyer, most recently with Audi/Volkswagen.

Where the Accent has vertical taillights, the Rio’s are horizontal, emphasizing the width of the vehicle. Stepping up to the Rio’s SX sport grade nets buyers dual chrome exhaust tips. A spoiler is standard across all grades, including the base LX.

The new Rio sports Kia’s signature tiger-nose grille, now found on all models except the aging Sedona minivan. The nose is small and thin, with the large lower grille the visual focus in front. Notched headlamps are trapezoidal – quickly becoming the shape du jour for that component – and contributes nicely to the styling.

The Korean auto makers appear to be taking a page from Volkswagen’s old playbook by swathing all interior surfaces with soft-touch material.

The Rio is a convincing premium subcompact, with a cushioned dash cover; sturdy, airplane-cockpit-inspired switches; and thoughtfully patterned speaker grilles on the interior doors, which match well with the dot-dash-patterned seat fabric.

However, the hard-plastic pillars don’t match up to the Accent’s fabric-look pillars. The Accent also wins with its instrument-panel design, compared with the Rio’s relatively plain IP.

The Rio proves fun to drive on the expressway en route to Seoul from the summer playground of South Korea’s eastern coast. The ’12 EX hatchback, riding on 15-in. low-rolling resistance tires, is impressively stable, with German sport-sedan-like composure not seen in an earlier Accent test spin.

However, the engine strains above 2,000 rpm as the small 4-cyl. struggles up the steep hills of the mountainous terrain here. A wimpy tip-in that requires flooring the hatchback’s gas pedal for even mild acceleration doesn’t help.

Making ample use of the 6-speed automatic’s “manumatic” function and downshifting to fifth gear makes up for this frustrating calibration. Perhaps Kia was stung by criticism of the super-touchy gas pedal in the Forte Koup.

The auto maker says it will introduce stop/start technology on all Rio models early next year. Rios offered in Europe already have the technology, but it proves of little use here, even during Seoul’s rush hour.

The few occasions where it was necessary to come to a full stop, the engine turned off as expected, but the restart came with a noticeable shudder. That’s in contrast to Japanese hybrids with stop/start that transition smoothly thought the modes.

Still, for a sub-$20,000 car, it’s nice to see Kia offering this technology, which should raise the Rio’s fuel economy 1 mpg (0.4 km/L). Pricing still is being debated, but executives here say the system, which Kia calls Integrated Stop-Start, should add about $350-$400 to the ’12 Rio’s price.

The Rio has a rigid ride thanks to the cost-conscious torsion-beam rear suspension. The front uses a MacPherson strut, with coil springs and a stabilizer bar. Smooth roads here are not so jarring. But imperfect pavement likely will make for a rough ride, especially for buyers who opt for the more athletic SX model, fitted with 17-in. wheels.

The Rio’s standard electric power steering has a heavy feel at highway speeds, loosening up slightly in city driving, in keeping with the sporty character of the car.

The Rio returned 37 mpg (6.4 L/100 km) over a 116-mile (187-km) mostly highway route, with an average speed of 43 mph (69 km/h), according to the trip computer. Heavy city traffic near the end of the trip knocked back our observed high of 40 mpg (5.9 L/100 km).

The 5-door Rio is a few inches shorter than the Accent hatchback, almost 1 in. (2.4 cm) wider and a bit taller. Front passengers get a couple inches more legroom in the Rio at the expense of those seated in the second row, the opposite of the Accent.

Both cars share a 101.2-in. (257-cm) wheelbase that is longer than that of the Ford Fiesta but slightly shorter than the best-selling Nissan Versa.

The Rio 5-door goes on sale in the U.S. this month, with the sedan coming later this year, a testament to the growing popularity of hatches in the States. Kia expects the 4-door to appeal more to young women, while the hatch should attract active men.

The LX grade is relatively spartan in terms of amenities but does offer steering-wheel-mounted audio controls and a 60/40 split rear seat. The EX nets buyers power windows and door locks and keyless entry, while the sporty SX grade has power-folding, heated side mirrors with turn-signal indicators.

Options for the EX include stop/start and Kia’s new UVO infotainment system. The SX offers a special package with navigation, a 7-in. (18-cm) touch screen, push-button start, heated front seats, moonroof and leather seat trim.

Thanks to its European good looks, high-quality interior, good performance and fuel economy, the ’12 Rio should quickly find itself on buyers’ shopping lists, much like the Optima sedan and Sorento CUV have done.

cschweinsberg@wardsauto.com