Audi's TT Sportback concept features a 2.0-liter four-cylinder engine that puts out 400 hp.

Apparently, two new versions of the TT roadster weren’t enough for the brass at Audi, so the luxury arm of Volkswagen AG has decided to bring a third alternative to Paris for this year’s auto show.

For now, the 400-horsepower TT Sportback is being described as nothing more than a concept, but from the way officials were talking during a Wednesday night preview, they seem very interested in the idea of adding a third body style to the Audi TT family, alongside the familiar coupe and roadster models.

The Sportback name has become a familiar one to Audi fans, though with the new TT concept it describes a five-door, coupe-like hatchback, rather than a wagon. The show car features a true four-seat layout with storage bins separating the two back-seat passengers.

There are a few of the usual show car excesses, such as the 21-inch tires and a laser spot that, Audi explains, “complements the LED high beam is featured in each of the headlights – this innovation from Audi significantly boosts safety when driving in the dark.” Nonetheless, the Audi TT Sportback Concept appears surprisingly close to production for a show car.

Audi's TT Sportback concept gets 56 mph while putting out 400 horsepower.

Measuring 14.7 feet in length, the Sportback is 11.4 inches longer than the new TT, and 2.4 inches wider, at 6.2 feet. It gains 4.7 inches in wheelbase, at 8.6 feet, but drops about 1.2 inches in height, at 4.5 feet.

(Audi bringing new TT and TTS models to Paris for debut. For more, Click Here.)

Whether Audi would actually put a 400-horsepower engine under the hood of a TT – even a stretched, four-door version – seems unlikely, however. In concept form, the 2.0-liter turbocharged four-cylinder package is said to be able to launch the car from 0 to 100 kmh (0 to 62.5 mph) in just 3.9 seconds. The Concept’s engine is paired with a dual-clutch gearbox that drives – of course – a Quattro all-wheel-drive layout.

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Audi's TT Sportback is a concept vehicle ... for now.

To turn out that much power, the 2.0-liter engine has undergone a variety of modifications, including the use of special aluminum pistons with integrated cooling channels, a crankshaft made of ultra-high-strength steel and a turbocharger capable of 1.8 bars of boost.

Surprisingly, Audi suggests the package could deliver fuel economy of up to 56 mpg in the U.S. driving cycle.

(To see more about the Corvette that blasts into sub-3-second zero-to-60 club, Click Here.)

“With the TT, Audi created one of the automotive design icons of the last 20 years,” said Ulrich Hackenberg, the Audi Board Member responsible for Technical Development. “In the years since, we have designed our sporty and elegant five‑door Audi A5 Sportback and Audi A7 Sportback. In our Audi TT Sportback concept show car, we are now fusing both concepts to form a new member of a potential TT family.”

How serious is Audi about building the TT Sportback Concept. From the tone of the talk on Wednesday night, one has to say quite serious. And that means we could be seeing the show car make a return in production trim in the near future.