The 2006-2007 WRX rims are offered from factory for the Impreza RS as you said, there won't be any significant differences between your car and an RS in that regard and they'll fit fine. If you can, try to find a set with 225/45R17 tyres - these were offered on the later GD chassis WRX (2005-2007) and will be a lot closer to the correct rolling diameter for your car. Keep in mind that there'll be a speedometer difference between bald and new tyres too.

Here's a good website to compare what will happen when you change the wheels.

205/55R16 vs. 225/45R17

205/55R16 vs. 225/50R17t