The Cadillac CT6 makes its official debut the night before the opening of the 2015 NY Auto Show.

With the official unveiling of its new CT6 sedan, Cadillac is setting out to “reinvent the premium luxury segment, global president Johan de Nysschen declared Tuesday evening. But the debut of the big sedan is also about reinventing the once-dominant Cadillac brand itself.

In the works since late 2009, shortly after parent General Motors emerged from bankruptcy, the Cadillac CT6 will go up against some of the world’s toughest competitors, vehicles such as the Mercedes-Benz S-Class, BMW 7-Series and Audi A8. But Caddy officials insist they went to play the game on their own terms as they begin an $8 billion product program that will more than double the breadth of the brand’s current line-up.

The process began with the debut of the small ATS and mid-range CTS, and now moves to the premium segment where Caddy hasn’t been a significant player in years. “The challenge, us to reinvent the large luxury segment, a category Cadillac once called its own,” said de Nysschen, during a preview ahead of the official opening of the New York Auto Show.

The new Cadillac CT6 has a 122.4-inch wheelbase, about eight inches longer than the latest-generation CTS model, noted chief engineer David Leone. But it will actually be 4.5 pounds lighter. By another measure, it has about the same length as the BMW 7-Series but weighs only about as much as the smaller 5-Series. That will translate into a vehicle both more fuel-efficient and nimbler than traditional premium luxury models, Cadillac officials claim.

The CT6 will be about the size of BMW 7-Series but weigh barely as much as a 5-Series.

To get there, the Detroit luxury maker has adopted an “aluminum-intensive” platform, but did not opt for the all-aluminum approach of competitors such as Audi. The goal, stressed de Nysschen, was to come up with “the right materials for the right parts and components.”

Key structural beams, for example, are made of extruded aluminum, while the doors are stamped aluminum. The floor pan and instrument panel firewall, on the other hand, use a sandwich steel and resin construction to minimize noise. In all, 13 different materials are used for the body and chassis of the CT6.

Initially, Cadillac will launch with three different powertrains, including a fuel miserly 2.0-liter Turbo, a new 3.6-liter V-6 and a new 3.0-liter twin turbo with one of the highest outputs per liter of any engine in the world, producing a total of 400 horsepower and 400 pound-feet of torque.

Cadillac's new twin-turbo V-6 was designed to deliver plenty of power while maximizing mileage.

Other powertrains are reportedly in the works, including a diesel, and a plug-in hybrid, the latter expected to be announced during the upcoming Shanghai Motor Show. A safe bet is that Cadillac will eventually launch a V-Series version of the CT6. If it falls in line with the recently introduced CTS-V model, it would likely deliver in excess of 600-hp.

(For more on the new Cadillac CT6 engine line-up, Click Here.)

The launch powertrains will be paired with a new 8-speed automatic transmission and be offered with All-Wheel-Drive. The system will also allow torque vectoring to enhance cornering, especially under aggressive maneuvers. And an Active Rear Steering system will further improve cornering.

The new Cadillac flagship will use the brand’s familiar Magnetic Ride Control suspension which can continuously vary the dampering of each individual shock in about the time it takes to travel one inch at 60 mph.

The new CT6 will use indirect-firing LED headlamps and LED running lights.

During his presentation, de Nysschen, a former Audi and Infiniti executive, took a few shots at Cadillac’s import rivals, at one point noting the heavy battle cruisers launched during World War II from the Brooklyn Navy Yard where the CT6 preview was staged.

The reality is that it will be a tough challenge to take on players like Mercedes and BMW which sold substantially more vehicles in the U.S. than Cadillac sold worldwide in 2014.

The new Caddy sedan clearly took some pointers from the likes of the S-Class and 7-Series. Its interior features the elegantly detailed use of premium materials like leather, wood, aluminum and carbon fiber. It can be ordered with heated, cooled and massaging seats, front and back.

(For more on Cadillac’s grand product program, Click Here.)

The CT6 interior will be completed with a lush mix of upscale materials, including leather and wood.

The CT6 will be loaded with many of the high-tech features that wowed premium luxury buyers when the latest S-Class debuted in 2013, including infrared Night Vision. It also adds a few new touches, including the industry’s first Rear Camera Mirror. With the flick of a switch, the standard rearview mirror’s image is replaced by one showing images from a camera that eliminates obstacles such as headrests.

Visually, the new Cadillac CT6 picks up on the basic Art & Science design language first introduced a decade ago with the original CTS model. But it is a bit less edgy, reflecting the more sophisticated segment it competes in.

Wide and low, with the wheels pushed out to the corners, “This is the next step in the continuing evolution of Cadillac,” said chief designer Andrew Smith. But he also noted the CT6 retains some trademark Caddy design cues, such as the vertical headlamps. In this case, however, they use sophisticated new indirect-firing LED bulbs, he noted.

All four seats will be available with heated, cooled and massaging functions.

The development of the CT6 was influenced by GM’s growing presence in China, which is expected to soon become the world’s largest luxury car market. GM is currently the second-largest maker there, behind only Volkswagen AG – whose Audi brand leads the Chinese luxury market.

The version of the CT6 to be launched in April at the Shanghai show is expected to add some key features attuned to the desires of a market where high-line buyers often prefer to be chauffeured. A plug-in version will also be introduced there first.

The debut of the Cadillac CT6 comes during the same week in which long-time, crosstown rival Lincoln will get back into the premium segment with the debut of the new Continental sedan. But where the two marques traditionally went head-to-head with relatively similar products, Lincoln is steering in a different direction, the new Continental emphasizing “quiet” luxury, according to company officials, rather than what they described as the “aggressive” luxury of competitors like BMW and Cadillac.

(Click Here for the full story on the new Lincoln Continental.)

Whether U.S. – or Chinese – buyers will warm back up to either of the Detroit offerings is far from certain, but the reception the CT6 and Continental receive will be critical to the turnaround of the two brands.

Caddy doesn’t expect large sales numbers. The exclusive segment is more about setting the theme for a brand. And, in Cadillac’s case, the CT6 shows the direction Cadillac will be taking as it rolls out the rest of its new line-up over the next half-decade.