While Subaru refused to make major changes to the WRX’s silhouette, improvements made to the mechanics and platform make it a much better car than the one it’s replacing. The engine output, driving pleasure and handling have all been increased. The WRX’s 2.0L four-cylinder turbo boxer engine produces 268 horsepower. As for the WRX STi, the 2.5L turbo gives the driver access to 305 horsepower.