The WRX's 2.5-liter four-cylinder gains a whopping 41 hp for a total of 265, thanks to a turbocharger that's now as large as the STi's but configured slightly differently. The turbo produces more boost (13.3 psi) than the 2008 WRX, with a steeper torque curve that now peaks 18 lb.-ft. higher, at 244. A freer-flowing exhaust reduces back pressure by 30 percent and helps all that air escape the engine. A larger intercooler and reprogrammed ECU are optimized for the beefier engine too. Highway fuel economy is unchanged at 25 mpg, while the city figure drops a click to 18 mpg—not a bad sacrifice considering the significant increase in power.
Built on the same 103.1-in. wheelbase platform as the 2008 model, the '09 WRX now wears STi-type front-upper-strut mounts, increased spring rates, and thicker front and rear sway bars. In keeping with the stouter suspension componentry, the WRX gets 17-in. aluminum-alloy wheels and replaces last year's all-season rubber with 225/45 summer performance tires. A new damper valve in the steering gearbox helps the suspension cope with the bigger rubber.
Ahí está más menos claro cuáles son las diferencias.
