America, it's your new Cadillac CT6

This is the brand new Cadillac CT6, launched at the 2015 New York Motor Show as a big, luxury rival to Merc's S-Class. But, strangely, it's not actually all that big.

Well, fat, anyway. Cadillac tells us that this all-new CT6 - short for Cadillac Touring 6 - makes extensive use of aluminium and steel in its structure. Indeed, we're told 64 per cent of the base, and all of the exterior body panels, are fashioned from the stuff. So it's promised to be light. We don't know precisely how light, but it's quoted as 91kg lighter than an equivalent steel-structured Caddy.

There's more new stuff too. A new 3.0-litre twin-turbo V6 is slotted in up front, with cylinder deactivation for better fuel economy and lower emissions, matched up to a new eight-speed automatic gearbox with three driving modes, and all-wheel-drive.

So, it's a light, V6-engined, all-wheel-drive luxury US cruiser that, Cadillac reckons, should be experienced from the front seat, not bad. Those dampers are active - the same Magnetic Ride Control tech found on the Corvette - together with active rear steering, which Caddy president Johan de Nysschen (formerly of Infiniti) reckons makes the CT6 a "sovereign presence" that's "light and agile on its feet; a true driver's car".

And quick, too, thanks to the whopping 400bhp and 400lb ft of torque from that twin-turbo V6, although a lesser-powered 2.0-litre turbo is also on offer. Plus, there's a brand new 3.6-litre, naturally aspirated V6 on the way, too. All petrols, naturally.

Inside it's all modern luxury, with the choice of many trim options - from wood, leather and carbon fibre - to massaging comfort seats, a pair of high-definition screens mounted on the back of the front seat headrests, and even tech like night vision with pedestrian recognition.

And to keep America's hearing specialists in business for the foreseeable future, Bose has actually developed a new audio line specifically for Cadillac, dubbed ‘Panaray', which features no fewer than 34 speakers. Thirty-three speakers plunges you back into the Dark Ages, obviously.

"This is our flagship Cadillac," de Nysschen said, heralding the CT6 as "one of eight model" arriving in the near future, in five new market segments. Have a click through the pics and let us know what you think of the big bad Caddy.