Everyone is going to tell you to lose the intake.

 

1. Lose the cold air intake.

2. Downpipe and uppipe

3. Engine management

That's the power route. I assume that's what you want? (As opposed to handling/suspension mods?)

 

ahem

 

you know what... ppl say CAI deperform (is that even a word???) your car. In REAL english, CAI sucks, its gives you less power. Stock air intake is good enough. I read about some sites saying that subaru made their imprezza's so their intake and exhaust matches, so no need for extra money on the intake. You might wanna consider a bigger turbo and a larger tmic/fmic.

 

yes put the stock intake back on . . . most people run stock intakes with a filter change or the get a short ram. sell your intake! . . . hopefully SOMEONE will buy it !

 

+1 ! Follow this exactly for real power gains !

 

There are three rough criteria for replacing the stock intake with an aftermarket one: 1.) 300+ crank horsepower, 2.) Aftermarket turbo, 3.) Front mount intercooler. Of these 3 criteria, only #3 requires that you change your intake (since it is physically impossible to use the stock intake with a front mount intercooler). When you do meet one (or two or all) of these criteria and go shopping for an aftermarket intake, go for a high-flow short ram design. Recommended models are HKS Racing Suction, Blitz SUS, Blitz LM, ARC Induction Box (particularly recommended for off-roading applications or other situations where air may be exceedingly dirty), etc.

I do not recommend cold air intakes for a number of reasons that I have stated time and again here, and if you are curious to view my and others' arguments, feel free to read the "Sticky" thread "The Cold Air Intake Debate" at the top of the power section's page. You'll see that many old school members like myself find the cons of cold air intakes to outweigh the pros.

 

I've had 2 WRXs (an 02 and the 04 I have now). I have run a lot of intake set ups. CAI was the worst.....it got beat up in the snow, and seemed to decrease torque. Next I put the stock intake box on with a Green filter. This worked well, but sounded wierd...I think this was better than stock though...grunt wise. After that I got a unifilter ram intake. I still have this and it was LOUD. Probably increased air flow at higher rpms it seems. That was all on my 02 WRX. On my 04 I have a cone filter ram intake. This works well and I think this makes more power on the highway....of course I have a catless up-pipe and a bunch of other stuff. I have had NO problems with any of these intakes.