Originally Posted by pilfflip
You might also look into some sort of intake-the easiest way to get power out of a N/A engine is to make the air enter and exit the engine easier.
Intakes show very little to no gains on Subarus. They're expensive noisemakers on these cars. Exhaust however, does have some promise.
I would support the idea that a lightweight crank pulley or a lightweight flywheel would make a nice gain. If anyone makes performance cams they can make a difference. PnPing the heads would allow for some more flow. Engine management is definitely a must if you're going to get serious.
The problem is, a lot of people have found its way too expensive to get anything significant out of the EJ25 N/A motors. When all is said and done, a WRX swap would do more for about the same money.