Subaru is cooking up a WRX STI storm, with the next-generation performance hero due next year to come armed with a 2.4-litre turbo-petrol engine producing a staggering amount of power and torque, according to an overseas report.

Citing sources close to Subaru, Forbes reports the new boxer four-cylinder unit, codenamed FA24, will be good for 298kW of power and 489Nm, which would put the incoming WRX STI on the same level as Mercedes-AMG’s 310kW/500Nm CLA45 S.

For reference, the 2.5-litre (EJ25) WRX STI currently in Australian showrooms ‘only’ develops 221kW/407Nm, so this would represent a massive performance upgrade.

The FA24 engine is already found in other Subaru models, including the Ascent SUV local buyers don’t have access to, in which it produces 194kW/376Nm.

In order to turn the wick up to the CLA45 S benchmark, though, mechanical upgrades will be made to the unit, including a reinforced crankshaft and pistons, fine-tuned valves and intake ports, optimised timing balance and tweaked boost pressure.

Of course, Subaru’s symmetrical all-wheel-drive system will be in tow to ensure optimum traction and therefore handling.

That said, no mention has been made of the next WRX STI’s transmission options. A six-speed manual is mated to the existing model.

As reported earlier this month, other rumblings overseas suggest the ‘regular’ WRX will also be offered with the FA24 engine, but its tune is said to be closer to that of the Ascent.

Interestingly, these same reports also indicated a lower-output version of the WRX will be available, too, powered by the 1.8-litre unit from the Levorg prototype revealed at the 2019 Tokyo motor show.