It's my understanding that the stock turbo on the WRX is decent for low end power but loses breath in the higher rpms....on a 2 liter engine. I would guess that this turbo would be too small for our 2.4 liter engine. This is just what I've heard. You may want to do a little research on the WRX's stock turbo. I myself would get something like a T3 super 60. Also, it's not just a matter of "OK I have a turbo and I want to put it on my car", it takes a few more things to make a turbocharger work with your engine, including exhaust manifold, charge pipes, fuel mods, intercooler (it'll be tough to get the Subie's to work), downpipe, etc.
If you're serious, do a little research and then come back and ask some more questions. I'd be glad to help, and I'm sure others would be also.
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