The Opel GTC Paris has been unveiled with images and details of the Astra based concept which will make its first public appearance at the Paris Motor Show at the end of this month.
The production version Opel GTC Paris will be called the Opel Astra GTC and this 3-door hatchback measuring 4.46 m in length, will extract power from a 4-cylinder 2.0-litre turbocharged engine with Start/ Stop technology and which will be linked to a 6-speed manual transmission.
Even though performance figures were not specified we suspect that the Opel Astra GTC will be something close to what its rival, the VW Scirocco outputs, plus an Opel Astra GTC OPC might also be part of the automaker’s plans. 
Some of the design cues at the exterior include the eagle-eye shaped headlamps, LED
taillights, Opel’s signature blade along the rocker panel, and a coupe like-roof line.
More details with the Opel GTC Paris and maybe even the Opel Astra GTC price should be announced as the car will premiere at the end of September. 
Opel press release :
Rüsselsheim.  Opel’s Vice President of Design Mark Adams gave his
team the briefing: “show me the most emotional side of Opel’s new design
language, ‘sculptural artistry meets German precision’.” What they
created, the GTC Paris concept car, will be shown for the first time at
the Mondial de l’Automobile 2010 (October 2 – 17).
Coming close on the heels of the new generation Astra Sports Tourer,
which will also debut at the Paris motor show, the GTC Paris is the next
bold step of a newly shaped Opel line-up.
Inspiration for the concept was partly derived from a quote from Richard Bach’s famous novel, Jonathan Livingston Seagull   “…and the speed was pure beauty.”
This phrase is embodied throughout the character of the car with
dynamic sweeping lines, beautiful sculptural surfaces, and a wide
muscular stance. This three-door compact is bold yet pure and is very
iconic in presence. The GTC Paris is conceived to be the obtainable
dream car delivering German engineered precision and innovation, matched
with eye-popping design.
“We wanted to express the most emotional side of the Opel brand and
we believe this vehicle creates an appropriate visual impact to
reinforce our dynamic sporty character,” Adams said.
Distinctly a new Opel – with an emotional tribute to performance
At 4.46 meters, the GTC Paris is the ideal size for a compact, sporty
car, but it still offers room for five passengers. Most iconic cars
have been drawn from the side. Many can be sketched with two or three
sharp lines. So, too, with Opel’s new concept car: In profile, the
designers have maximized tension by limiting the amount of lines in the
GTC Paris. Similar to tendons in a sprinter, these lines create tension
and provide a sculpted shape. They serve as the foundation to which the
highlights and surfacing react and press to the wheels in a very
athletic fashion.
The Opel signature blade is introduced in the same direction as first
seen in the Insignia – a fine, tense crease along the rocker panel. A
second line shoots from the door handle to the rear, emphasizing the
vehicle’s dramatic stance by spreading the surfaces to a fine undercut
and a broad shoulder. The third line following the silhouette of the
roof is finished in finely brushed aluminum that accentuates the window
graphic, guiding the eye to the sharply distinct integrated spoiler.
The front is clean yet full of character and features Opel’s typical
centerline crease. It is further accented by intense, very slim
eagle-eye shaped headlamps acting as parenthesis between the refined
chrome emblem bar and the dramatic low trapezoidal grill which hints at
its sporty character. Signature LED daytime running lights are outlined
with finely crafted chrome inserts that can stand as a piece of
sculpture by themselves.
The wide stance is accentuated in the rear, where the proportion of
the vehicle is most imposing. This is further enhanced with the LED
taillights showcasing a long, stretched “wing” nighttime graphic.
Innovative technology enhances performance
The best of Opel’s compact car technology is brought to its sportiest
level on the GTC Paris. The chassis has a special design with an
extra-wide stance. It features a compound crank with an Opel-exclusive
Watt’s link in the rear, a new, updated execution of the adaptive
mechatronic FlexRide suspension and a front electronic limited
slip differential. The GTC Paris is planted to the ground with dynamic
21-inch wheels.
The powertrain in the GTC Paris is a four-cylinder, 2.0 liter Turbo
with direct injection, packing maximum horsepower and torque. It is
fitted with Start/Stop technology, proving that drivers can combine high
performance with maximum fuel efficiency in urban driving conditions.
The transmission is a six-speed manual gearbox.
Vauxhall press release :
    * Three door Astra-based concept stars on Vauxhall’s Paris Show Stand
    * Dynamic, sweeping lines make bold statement about Vauxhall’s design evolution
    * Innovative suspension and drivetrain features hint at performance remit
Luton–These are the first official pictures of Vauxhall’s GTC Paris Concept, which gives the strongest hint yet to the Astra Sport Hatch’s successor and is set to cause a stir when it receives its debut on September 30 at the Paris Motor Show.
Mark Adams, Vauxhall/Opel’s Vice President of Design, has described the GTC Paris as, ‘bold, pure and iconic’ in its appearance. Vauxhall has hinted that a production version will not stray far from the rakish lines of the concept, and if the GTC moniker were to be adopted, it would be the first time that a Vauxhall has been so named.
At 4.46 metres, the GTC Paris offers ample space for five people, yet still maintains a svelte and sporting appearance. Adams’ team has maximised ‘tension’ in the design by limiting the amount of lines in the car’s profile, and leaving the impression that the car’s highlights and surfacing are ‘pressed’ on to the concept’s 21-inch wheels.
Vauxhall’s signature blade mimics that on the Insignia and creates a fine, tense crease along the rocker panel. This combines with a second line running from the door handle to the rear of the car, emphasising both a fine undercut and broad shoulder. A third line following the silhouette of the roof is finished in fine brushed aluminium accentuating the window graphic and leads to a sharply accented integrated spoiler.
Slim, eagle-eye shaped headlamps, flanked by LED running lights with chrome surrounds dominate the front of the GTC Paris. A sharp centreline crease runs down the bonnet (a trademark styling cue from Vauxhalls of yore) and leads to a dramatically low trapezoidal grille incorporating a chrome emblem bar.
At the rear, the imposing features of the concept are enhanced with LED tail lights, showcasing a long, stretched ‘wing’ night time graphic.
Underpinning the GTC Paris is a specially designed chassis with an extra-wide stance. Hinting at the car’s power potential is an electronic limited slip differential and an updated version of Vauxhall’s FlexRide adaptive damping system. The new Astra’s unique compound crank / Watt’s link rear suspension provides excellent packaging and secure, driver-focused dynamics.
A four-cylinder, 2.0-litre turbocharged engine, with direct petrol injection and Start/Stop technology is mated to a six-speed manual gearbox, providing drivers with high levels of performance and fuel efficiency.
More details about the GTC Paris Concept will be revealed before the Paris Motor Show.

Source: Opel / Vauxhall