Details with the North American version Opel Insignia a.k.a. the Buick Regal GS have been revealed today by GM.
What is different about the Buick Regal GS is that the US manufacturer decided to replace the 325 HP 2.8-litre engine found in the European version with a 2.0-litre unit that packs 255 HP (190 kW) and 400 Nm of torque (295 lb.-ft.). With this new engine the Buick Regal GS in able to sprint from 0 to 60 mph in under 6.0 seconds and so far top speed figures have not been released.
Other mechanical elements that were developed for the Buick Regal GS include a performance-oriented drivetrain and a lowered suspension while inside the cabin a sports-steering wheel with metal pads and Recaro front seats have been fitted.
The Buick Regal GS sits on large 20 inch wheels wrapped in performance tires, high-performance Brembo brakes with 14 x 1.2-inch (355 x 32 mm) cross-drilled rotors and power is put to the ground via a 6-speed manual transmission and the vehicle’s adaptive all-wheel-drive system.
The Buick Regal GS price was not announce yet.
GM press release :
DETROITWith an estimated 255 turbocharged horsepower (190 kW), a six-speed manual transmission and an advanced, adaptive all-wheel-drive system, the Buick Regal GS show car is a high-tech, high-performance version of the brand’s newest sport sedan. It was introduced at the 2010 North American International Auto Show.
The mechanical elements were developed with the aim of delivering a driving experience that is sporting, confidence-inspiring and refined. It has a performance-oriented drivetrain, a lowered body and lower center of gravity. Exterior and interior cues include two additional vertical front air intakes; large, forged aluminum 20-inch wheels and performance tires; a racing-inspired sport steering wheel and metal pedals. Recaro high-performance front seats feature four-way lumbar support and cushion extensions.
“We designed the Regal GS to explore the appeal of a high-performance variant of the Regal,” said Craig Bierley, product marketing director for Buick. “Like the Regal, the Regal GS is based on the award-winning Opel Insignia, and we believe it will reinvigorate Buick’s storied Gran Sport legacy.”
The Regal GS exterior is distinguished by vertical air inlets in the front fascia, as well as unique rocker panels, an integrated rear spoiler, dual exhaust outlets, Olympic White paint and satin metallic accents.  
“The idea behind the Regal GS was taking the production model in a more aggressive direction to appeal to performance enthusiasts,” said John Cafaro, Buick design director. “But along with its aggressive stance, there’s sophisticated style in the design that complements the driving experience.”
Inside, the Regal GS varies from the standard Regal by featuring a completely jet black interior, including the pillars and headliner, sport shifter for the six-speed manual transmission and a suede-covered, flat-bottom steering wheel reminiscent of those used in international racing series. The instrument panel glows ice blue when the driver engages the sport mode of the Interactive Drive Control System (IDCS).
Turbocharged AWD performance
Power for the Regal GS comes from a high-output 2.0L Ecotec turbocharged engine with direct-injection technology. It is based on the engine that will be offered on Regal CXL models later this summer, but the engine and turbocharger are tuned to deliver greater boost pressure in the GS. The output is estimated at 255 horsepower (190 kW) and 295 lb.-ft. of torque (400 Nm).
The engine is mated to a six-speed manual transmission that directs torque to an adaptive all-wheel-drive system calibrated for performance driving. An electronic, limited-slip rear differential helps ensure the engine’s power is distributed effectively during cornering.
The high-performance drivetrain is expected to enable the Regal GS to accelerate from 0 to 60 mph in less than 6 seconds. That performance is complemented by a four-wheel-independent suspension, with a unique High Performance Strut (HiPerStrut) design in front. The HiPerStrut system helps reduce torque steer and maintain negative camber during cornering. This improves ultimate grip levels in dry and wet conditions, as well as improves the direct feel of the road, while isolating undesirable feedback. Behind the wheel the driver experiences reduced torque steer, improved grip and increased cornering power, along with crisper handling, steering precision and feedback.  
The Regal GS features a high-performance Brembo brake system with 14 x 1.2-inch (355 x 32 mm) cross-drilled rotors; four-piston, high-strength aluminum calipers, and high-performance pads.
The Regal GS is also equipped with Interactive Drive Control System (IDCS) chassis technology (also offered on Regal CXL models with the 2.0L turbo engine). It delivers enhanced vehicle stability and greater driving safety, while also adapting the driving characteristics of the car to the driver’s preferences. The driver selects among three operating modes – normal, sport and GS – that change the suspension settings, throttle response and steering sensitivity through the variable-effort steering system.
BUICK REGAL GS SHOW CAR SPECIFICATIONS
Overview

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Model: Buick Regal GS show car
Body style / driveline: four-door, 5-passenger, front engine, transaxle. All-wheel-drive midsize vehicle
Construction: steel body-frame integral (unibody)

Engine/Transmission

High-output 2.0L DOHC I-4 Turbo
Displacement (cu in / cc): 122 / 1998
Bore and stroke (in / mm): 3.39 x 3.39 / 86 x 86
Block material: cast aluminum
Cylinder head material: cast aluminum
Valvetrain: overhead camshafts, four-valves per cylinder, continuous variable valve timing for intake and exhaust
Ignition system: individual coil-on-plug
Fuel delivery: direct injection with variable high-pressure rail and electronic throttle control
Compression ratio: 9.2:1
Horsepower (hp / kW): 255 / 190 (est.)
Torque (lb.-ft. / Nm): 295 / 400 (est.)
Transmission 6-speed manual
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Chassis/Suspension

Front: independent, HiPerStrut-type with dual-path mountings, specifically tuned coil springs, direct-acting stabilizer bar (hollow); hydraulic ride bushings; continuous damping control (Interactive Drive Control System)
Rear: four-link independent rear; hollow stabilizer bar; continuous damping control
Traction control: adaptive all-wheel drive; StabiliTrak electronic stability control
Steering type: hydraulic, variable-effort rack-and-pinion power steering

Brakes

Type: four-wheel disc w/ABS (w/ESC)
Brake rotor diameter
(in / mm) caliper type (front and rear):
14 / 355, vented and cross drilled rotors; four-piston aluminum calipers

Wheels/Tires

Wheel size and type: 20-inch aluminum
Tires: Bridgestone 245/35ZR20

Dimensions
Exterior

Wheelbase (in / mm) : 107.8 / 2738
Overall length (in / mm): 190.2 / 4831
Overall width (in / mm): 73.1 / 1811
Overall height (in / mm): 58.4 / 1483
Front track (in / mm): 62.4 / 1585
Rear track (in / mm): 62.5 / 1587
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Interior

Seating capacity (front / rear): 2 / 3
Headroom (in / mm): 38.8 / 985 (front)
36.8 / 935 (rear)

Note: Information shown is current at time of publication.

Source: GM