Tech note: The Subaru WRX comes in several distinct body styles. The 2002-03 models have round headlamps. The 2004-05 models got revised headlamps and tail lamps, different front and rear bumpers, front fenders, and hoods. The 2006-7 model again sported a revised front end, with new headlamps, fenders, hood, and front bumper. In 2008 the new body style was released -- see picture above.
All 2002-07 Impreza and WRX share the same trunk lid, but the rear bumpers are different, and 2002-03 have different tail lamps than the 04-07 models.
2008-10 WRX models had a narrower body than STI models, but in 2011 the WRX switched to the same wide body as the STI.