Here is the info from AutoBlog.com
It's official folks. Those of you that picked up a 2008 Subaru Impreza WRX have been had. The road-going rally rocket gets an update for 2009 and with it comes a retuned 2.5-liter boxer four-pot producing 265 hp and 244 lb.-ft. of torque – a 41 hp and 18 lb.-ft. increase over the outgoing model. Power will be sent to all four wheels through a five-speed manual – the only transmission available -- with low-profile 225/45R17 summer tires replacing the 205/50R17 rubber of the 2008 model.
The suspension has been revised to include stiffer springs, uprated dampers, upper strut mounts cribbed from the STI and larger anti-roll bars fore and aft. The Aero package is no longer an option – it's standard – and includes an STI-inspired grille on both the sedan and hatch, while the five-door receives the STI's rear spoiler and underbody diffuser.
Impreza obsessives that ran out to buy a 2008 model might be miffed, but Subaru had to make adjustments to keep the WRX competitive, particularly with the Mitsubishi Lancer Ralliart becoming a serious contender in the turbo'd sedan segment.