The latest news to leak out of Subaru is as red hot as it is shocking. Remember how the international media called the silver Advanced Tourer Concept at last year's 2011 Tokyo Motor Show the next-generation Legacy? Looks like everyone got it wrong -- including us. We're going to make up for that here, however, since we have just learned that the Advanced Tourer was actually an early look at the next-generation Subaru WRX. That's right folks, the highly-anticipated WRX has already been revealed in prototype form,

This artist's impression depicts what we have been able to scrounge from a Subaru insider about the company's all-new sports car. The new WRX will get headlights, air dam, grille, and front brake ducts like those on the Advanced Tourer Concept. The overall side profile will resemble the Tourer as well, though the new WRX will incorporate far more aggressive front and rear wheel arches and fenders. Odds are it will be bigger too -- at roughly 180 inches long, 72 inches wide and 56 inches tall, the Advanced Tourer is more than 6 inches longer, 3.5 inches wider, and almost 2 inches shorter than the all-new Impreza. Like the outgoing model, it will likely be offered as a sedan and hatchback.

Speaking of the Impreza, the WRX will diverge the way the Nissan GT-R completely diverged from the Nissan Skyline sedan in 2007. While it will ride on a heavily modified version of the current Impreza platform, the WRX will no longer employ the suffix Impreza. The harsh reaction to Subaru's attempt to appeal to a broader audience by softening the 2008 WRX's ride and handling traits planted the seeds for that radical decision. We also learned that in designing the new car, product planners aimed to redefine the WRX from a turbocharged boy-racer into a more-mature sporty grand tourer with a higher-quality interior. Make no mistake, however, the new WRX will come with a stiff suspension setup and enough power to satisfy even the most hardcore fan.

Speaking of power, a critical fact not yet clear is exactly what engines will motivate the new WRX. Our insider tells us that Subaru's R&D team is currently testing new FA series 1.6- and 2.0-liter direct-injected turbocharged boxer fours in addition to a hybridized version of the 1.6-liter turbo -- the powertrain featured in the Advanced Tourer Concept -- but he also says that while the R&D team is satisfied with the hybrid's mileage and emissions, they believe that the hybrid unit and its added weight wouldn't suit the WRX's performance focus. We're betting on the new 2.0-liter unit.

"There are those engineers who do support the hybrid idea, not least because the hybrid we are developing might employ some Toyota componentry. But the actual hybrid unit we are using is far lighter [than Toyota's THS-II] single-clutch design," explains our insider, adding that it was developed in-house. He told us that the current thinking inside Subaru is to channel the hybrid powertrain away from the WRX and into the all-new Legacy, due out in 2015. The new model will also incorporate a choice of the standard six-speed manual transmission or the updated version of Subaru's Lineartronic CVT fitted to the face-lifted Legacy that just went on sale in Japan.

The new WRX STIshould surface in 2015, and it will be aimed squarely at the U.S. market. It is expected deliver more than 320 horsepower (presumably from an optimized version of the new FA 2.0-liter turbo) and compete in WTCC and the Nurburgring 24 Hours, in which the current model recorded a dramatic class win last year.

This new WRX is part of Subaru's recently announced "Motion V" initiative, a plan to totally reinvent its powertrains and SI chassis, versions of which currently underpin both the Legacy and Impreza. "Expect to see more model downsizing and hybridization, while chassis will become even lighter and boast a higher quality finish," says our source.