SANTA BARBARA, CA – With acoustic laminated glass windows and strategically placed sound-deadening materials, Saturn Corp. engineers say they tried to make the new Aura the quietest midsize sedan on the market.

Indeed, over the occasional gravelly road and in the close-confines of a Southern California rush hour, the Aura is almost hermetically immune to street din.

The hushed ride is but one indicator Saturn is once again serious about playing tough in the midsize sedan segment – and the Aura underscores that with a quiet confidence.

The Aura fills the sedan hole left by Saturn’s unloved L-series, which the auto maker stopped producing more than two years ago. But to say the Aura replaces the L-series, which had an abbreviated ’05 run, would be a misnomer.

The front-wheel-drive Aura rides on General Motors Corp.’s global midsize architecture, which also underpins the Pontiac G6 and Chevrolet Malibu, as well as the Opel Vectra and Saab 9-3.

The Aura’s Adam Opel GmbH-inspired design, which is setting the new tone at Saturn, helps exorcise the brand’s reputation for uninspired sheet metal.

The halogen headlamps wrap upward and around the front corners, now a standard familial face for new Saturns, while the Aura’s taillights mirror those of the Sky roadster.

In a group photo, the new-look Saturn lineup (which includes the upcoming ’07 Outlook cross/utility vehicle) makes the current-generation Vue CUV look more like a distant cousin than a close family member.

The entry XE model and upmarket Aura XR, base priced at $20,595 and $24,595, respectively, undercut prime competitors, the Honda Accord and the Toyota Camry.

Saturn General Manager Jill Lajdziak declines to detail Aura production or sales estimates but anticipates sales mix will be about 80% XE and 20% XR.

XE models are equipped with a 3.5L OHV V-6 with variable valve timing (VVT), mated to the Hydra-Matic 4T45 4-speed automatic. The mill kicks out 224 hp and 220 lb.-ft. (298 Nm) of torque.

But given the importance GM and Saturn have bestowed upon Aura as a turnaround model, coming to market with a 4-speed automatic, even if only for the base trim, is a questionable tactic, given 5- and even 6-speed automatics now are the price of entry in this ultra-competitive segment.

The move up to XR models brings dual overhead-cam architecture in the form of GM’s 3.6L V-6. Also fitted with variable valve timing, the 3.6L V-6 is rated at 252 hp and 251 lb.-ft. (340 Nm) of torque. This markedly more contemporary V-6 also brings the benefit of the new Hydra-Matic 6T70 6-speed automatic.

Even with the upmarket 3.6L DOHC V-6, the Aura is edged out by V-6 variants of the Camry (268 hp) and Volkswagen Passat (280 hp) but out powers the Accord (244 hp) and Ford Fusion (221 hp) with smaller 3L sixes.

Nevertheless, the Aura XR's acceleration is brisk, with 60 mph (97 km/h) arriving from a dead stop in less than seven seconds, Saturn notes.

Saturn won’t be equipping either Aura trim with a manual transmission. But the 6T70, GM’s first application of its new, front-wheel-drive 6-speed automatic (co-developed with Ford Motor Co.) will provide manual shifting via steering-wheel-mounted paddles.

Fuel economy for the Aura XE is estimated at 20 mpg (11.8 L/100 km) city and 29 mpg (8.1 L/100 km) highway. The Aura XR delivers the same city mileage and delivers 28 mpg (8.4 L/100 km) on the highway.

During a test drive here, the Aura XR returned 21.2 mpg (11.1 L/100 km) on a varied route of twisting roads and straight highways.

With a wheelbase of 112.3 ins. (285 cm), the Aura stands a good 5 ins. (12.7 cm) or more longer between the axles than the Accord or Passat, but is within an inch or three of most other competitors in most exterior measures.

Inside, the little details justify Saturn’s boasts of refinement.

The interior trim loops around the instrument and door panels to nicely envelop the cabin. Finely stitched leather in Morocco brown embellishes the upscale feel of XR models. A chrome-covered slide opening covers the front cupholders and storage area.

The dash is encased in a spongy-to-the-touch plastic, which also lines the doorframes, to keep outside noise to minimum. The concave backs of the front seats – now a standard trick –allow a few more centimeters of legroom for backseat passengers.

There are a few details, such as the hard plastic center armrest, that are out of step with the rest of the interior. The amber-colored backlit driver-information and radio displays look great in the shade, but practically disappear in direct and even not-so-direct sunlight.

A constant creaking could be heard when one of the Aura XR production vehicles cornered to the right.

However, taut handling and a finely tuned suspension overcome those drawbacks. Steering could stand to be a notch tighter, with some play when the wheel returns to center. But the Aura tracks well in long curves and holds its own during tight switchbacks.

Of the two trims, only the Aura XR receives as standard GM’s StabiliTrak electronic stability control system to mitigate directional mishaps; traction control is standard for XE models.

The Aura models with OnStar will feature a new service called Turn-by-Turn Navigation, which allows drivers to find a destination with step-by-step directions downloaded to the vehicle by a live operator and played through the vehicle’s sound system.

Early next year, the Aura is tapped as the first GM passenger car to be fitted with the new “mild” hybrid-electric powertrain.

The same HEV setup premiers on Saturn’s Vue Green Line later this summer. The system comprises a 2.4L 4-cyl. mated to an integrated electric motor/generator that sits between the engine and a 4-speed automatic transmission.

GM will fit the hybrid driveline for an HEV variant of the ’07 Chevrolet Malibu, as well.

GM began shipping the Aura on July 31 and logged a sale on the same day in a Kansas City, KS, dealership, just outside the company’s Fairfax Assembly plant, which produces the Aura along with the Chevy Malibu and Malibu Maxx.

The Aura is designed to yank some import mid-level sedan owners to the brand and help Saturn establish a new foothold in the segment.

And with elevated fuel prices driving truck and SUV intenders toward midsize cars, enticing buyers escaping fuel-thirsty segments certainly means more in incremental volume today than it did a few years ago.

But in the battle for Accord, Camry and Passat loyalists, the Aura may not mount much of a challenge without a more powerful V-6 (GM reportedly will have a direct-injection gasoline variant of the 3.6L V-6 for ’08) or significant improvements in fuel economy that an eventual 4-cyl. variant might produce.

In the short term, however, the Aura’s refined interior, fine handling and neo-Euro feel may prove more tantalizing to buyers considering a Ford Fusion, perhaps.

scanderson@wardsauto.com