Subaru has announced both a new price offer and a performance upgrade on its iconic WRX STI.

Currently available for £26,995, the WRX STI is also available with a finance offer costing under £300 a month.

The new 340R power upgrade, which adds £1,599 to the price, is available alongside the 320R (with 320PS and 450 Nm) which was first launched to market last year. Both the 340R and 320R power upgrades can be applied retroactively without affecting a car's warranty.

Available immediately, the WRX STI 340R boasts 340PS and 490Nm of torque - substantial increases of 40PS and 83Nm over the standard WRX STI. The 340R power upgrade features different ECU settings to allow the 2.5-litre horizontally-opposed, four-cylinder Boxer engine to produce more power, while airflow has improved as a result of a new exhaust system.

The 340R will accelerate from standstill to 60mph in just 4.7 seconds, an improvement of 0.5 seconds over the standard WRX STI. There is also even stronger in-gear acceleration as a result of the improved torque.

As with other WRX STI models, the 340R benefits from Subaru's advanced All-Wheel Drive technology, Torsen rear differential, fully-independent front and rear suspension and four-door saloon practicality.