Specially developed in-house at Subaru UK, the 320R power pack takes the standard 221kW/407Nm 2.5-litre turbocharged Boxer engine, mounts it lower in the engine bay and increases performance to 235kW of power and 450Nm of torque.
As a result, acceleration from 0-100km/h drops from 5.2 seconds to 4.9 seconds, making it as fast as a Jaguar XFR.
All WRX STI 320R models will also get satellite navigation with a removable touch screen (for easier information downloading), as well as Bluetooth and USB/iPod connectivity.
The offer applies to both sedan and hatch variants, and best of all, does not add to the £32,995 ($51,950) price of the standard Subaru WRX STI. The vehicle will be sold exclusively in the UK.
Subaru Australia’s David Rowley said there were no plans in the immediate future for a higher performance WRX STI in Australia.
Mr Rowley said performance enhancements for local products were generally the result of close collaboration with the factory in Japan rather than exclusive special editions by Subaru Australia itself.