The latest generation Subaru Impreza debuted back in 2016 and there's still neither a WRX or WRX STI version. Subaru still sells the previous generation Impreza-based, rally-inspired hot sedans but not for much longer. Everyone knows - perhaps most of all Subaru - the pair are seriously outdated. Fortunately, replacements are due to arrive starting in 2021, according to a new report from Forbes.

This information supposedly comes directly come from "sources close to the Japanese automaker." The first thing you need to know is that there'll be more horsepower. A lot more. We already knew this was going to happen but that power boost is more significant than previously thought. These sources claim the next Subaru WRX STI will feature an all-new 2.4-liter boxer turbo, codenamed FA24, that will produce no less than 400 horsepower and 361 lb-ft of torque.

To compare, the current STI offers up 304 hp and 311 lb-ft. However, its 2.0-liter boxer turbo is also quite outdated. While it's been updated regularly, it dates back to 1989 and its time is finally up. Serious Subaru fans will also recognize that the FA24 is the same engine currently found in the popular Subaru Ascent three-row crossover. Clearly the Ascent doesn't offer upwards of 400 ponies, so what will be different for the next WRX STI?

The reworked FA24 will receive a reinforced crankshaft and pistons, optimized timing balance, improved boost pressure, and updated valves and intake ports.

Sources claim the WRX's (not the STI) 2.5-liter boxer turbo, internally called EJ25, will remain in service until after the next WRX arrives, likely sometime after 2021. The general exterior styling direction, at least for the next STI, has already been previewed by 2017's Viziv Performance Concept. Subaru has a history of producing bold-looking concepts only to see them significantly toned-down on the eventual production model.

We'll have our answer next year when the all-new Subaru WRX STI is scheduled to debut.