Subaru debuted the WRX performance variant of the third generation series in April 2007. Power output consists of 169 kW (227 hp) and 320 N⋅m (236 lb⋅ft) from its 2.5-liter engine. In response to criticism that the third generation WRX suspension is too soft, and needing to keep on par with rival car companies new releases, Subaru issued several changes in 2008 for the 2009 model year. The EJ255 engine received an output boost to 198 kW (265 hp) and 331 N⋅m (244 lb⋅ft) of torque by swapping the previous TD04 turbocharger to an IHI VF52. This led to the car now achieving a 0–60 mph (0–97 km/h) time of 4.7 seconds.
Debuting at the Tokyo Auto Show in October 2007, the STI in Japan was fitted with the 2.0-liter EJ207 engine with twin scroll turbocharger generating 227 kW (308 PS) and 422 N⋅m (311 lb⋅ft) of torque at 4,400 RPM. Export markets receive the higher-displacement 2.5-liter EJ257 unit with the single-scroll VF48 turbocharger rated at 221 kW (300 PS) and 407 N⋅m (300 lb⋅ft) of torque. The turbocharger directs air through a larger top-mount intercooler which has lost the red “STI” that was on previous generations. The STI (3,395 lbs) is heavier than the WRX (3,174- 3,240 lbs depending on trim) due to a more robust transmission, rear differential and other chassis reinforcements.