Buick has introduced a larger, more sophisticated Regal for 2018. The car comes in liftback (Regal Sportback) and wagon (Regal TourX) body styles in the United States, but skips the more traditional notchback sedan shape offered in China.

Also missing is a sporty GS variant, though one is coming. Our latest spy shots show the GS version of the Regal Sportback out testing.

We know this is the Regal GS Sportback because of the more aggressive front bumper design, subtle aero kit, enlarged wheels, and square-shaped exhaust tips at the rear. Leaked shots of the Chinese-market Regal GS sedan hint at what’s to come.

Leaked images of Chinese Buick Regal GS

Leaked images of Chinese Buick Regal GS

What isn’t so clear is what actually is lurking under the hood. Information that briefly appeared on Buick’s Canadian website in April suggested that the Regal GS will come with a 3.6-liter V-6 and all-wheel drive. This same setup will be offered in the Regal’s corporate cousin destined for the Australian market, the NG-series Holden Commodore.

In the Commodore, the V-6 is set to deliver 308 horsepower and be mated to a 9-speed automatic. It’s possible we’ll see a few more horses for the Regal GS. The outgoing model draws 259 hp from a 2.0-liter turbocharged inline-4.

Look for a debut late this year or early next. Sadly, only the Regal Sportback is expected to receive the GS treatment in the U.S. That means you can forget about a modern Buick Sport Wagon.