It would probably be safe to assume that this slightly different structure is safer, but the Insurance Institute for Highway Safety now separates the two series of models and hasn't yet tested the WRX family. The IIHS gives the 2011 Subaru Impreza top 'good' ratings for frontal offset, side impact, and roof strength, and it earns the Top Safety Pick designation, but the IIHS notes that those ratings do not extend to these performance models—presumably because there are now enough structural differences between the models.
Although the 2011 Subaru Impreza WRX and STI haven't yet been rated by the federal government, according to its heavily revised 2011-model-year crash-test system, the previous 2010 models carried five-star frontal ratings and four- and five-star side-impact ratings.
The 2011 Impreza WRX and STI models have a number of additional features and attributes that make it a very safe choice. All Impreza variants come with side impact and side curtain airbags, electronic stability and traction control, anti-lock brakes with brake-force distribution and brake assist, and daytime running lamps as standard. Manual models also get hill start assist. And finally, as with any Subaru model, standard all-wheel drive proves invaluable during inclement weather.