A cold air intake won't add much and in fact will put the car at risk. The stock ECU won't properly scale the MAF and without a tune, if you install a cold air intake you risk the car running dangerously lean and destroying the motor. It is not worth the risk, plus the stock intake has been proven to flow plenty of air for the stock turbo. You are better off investing $150-$200 into a custom tune. It will be safer and you will get much more power out of the car that way. Turbocharged Subarus are not like Civics where the first thing you do is slap an intake and exhaust. Research and invest your money wise.
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