Yeah but how easy is it to find a WRX engine, I'm guessing they're not laying around in junkyards yet. If you can get a good deal on a wrx engine, and sell the other turbo parts that would be awesome. Just go for whatever is more practical. If this is your daily driver, I would add Billy's turbo parts on to it. But it's true how bad DO you want it, if I were you and owned a 2.5RS Impreza I would want it pretty damn badly. Speed is priceless baby