Saab Automobile AB, just weeks away from breaking loose from General Motors Co. and going under the wing of niche auto maker Koenigsegg Group AB, releases the first images and specifications of the all-new Saab 9-5 sedan it plans to unveil at the Frankfurt auto show next month.

“This car is the start of a new era for our brand,” says Jan Ake Jonsson, managing director-Saab.

“We have created an advanced and very distinctive product by leveraging the power of our roots in key areas, such as progressive Scandinavian design, sporty driving and responsible performance,” he says in a statement today.

The premium sedan will ride on GM’s Epsilon II architecture, which also underpins the Opel Insignia in Europe and the Buick LaCrosse in North America and China, and Saab says it represents the most technically advanced vehicle ever from Trollhattan.

However, exterior styling of the 9-5 breaks cleanly from those cars through updated Saab design cues, such as the C-pillar “hockey stick” wrapping the side rear windows, and front-end elements from the well-received Aero X concept car introduced at Geneva in 2006.

Front and rear overhangs seem shorter than the current model, it appears to have a more planted, muscular stance, and the beltline is noticeably higher. The greenhouse compresses as it moves rearward to convey a sleek profile, although Saab says it stops short of emulating the coupe-like design popular for 4-door cars today.

Inside, Saab promises the brand’s traditional driver-focused cockpit, but updated in the same spirit as the exterior. The ignition remains between the front seats next to the gear shift, but is now a start/stop button.

The 9-5 also receives a thrifty lineup of turbocharged 4-cyl. engines, part of what Saab calls “responsible performance” as it enters a new era. Two 2.0L mills provide either 160 hp or 220 hp, with the less powerful engine a diesel and the up-level unit burning gasoline. The diesel generates 139 g/km of carbon-dioxide emissions, making it the most fuel-efficient in the lineup.

A top-of-the-range 2.8L turbo V-6 delivering 300 hp and 295 lb.-ft. (400 Nm) will be offered exclusively with all-wheel-drive models. A smaller 1.6L gasoline turbo with 160 hp will be offered shortly after the initial launch late in the ’10 model year

All models will receive a 6-speed transmission, although Saab does not indicate if a manual gearbox will be made available.

The 9-5 will feature two different suspensions, depending on engine power, and both include “Sport” settings.

The new 9-5 marks the start of a product offensive from Saab, an initiative that also includes a 5-passenger 9-4X cross/utility vehicle off a premium version of GM’s Theta Epsilon platform. That vehicle is due next year from GM’s Ramos Arizpe, Mexico, assembly plant, but will be the only future model from Saab engineered and built outside of Sweden, spokesman Eric Greers tells Ward’s.