Downpipe/CAI recommendations for 2.0 Turbo

[OtterCraft]

I am getting a Greddy cat-back exhaust, and have intentions of adding more flow from the turbo-back. What downpipe style do you recommend, and what is necessary to run it properly on my 2004 WRX? I am also considering adding a CAI along with the exhaust, but am not sure if it is a good idea being I see a lot of dirt roads with this Forester suspension. Will I have issues sucking in dust when off road if I add the CAI?

 

[Spiller1327]

Don't do a cai! Invidia catless down pipe ftw

 

[drvsdwz]

doesn't matter if cai or not, you're going to suck up just as much dust. the difference is going through puddles.

Question for you. What type of engine management will you be using? Reason I ask is that with a new intake, and especially the downpipe, you will need a tune so that your car runs properly. There are a few options with this.

 

[IBratmanI]

You have to choose between a catted down pipe and non catted. After you decide that, pretty much choose any decent quality exhaust. Invidia is a good quality as Spiller said. And no need for a cai. You can upgrade the panel filter on your stock air box. And you will need a tune, whether it's a protune from a reputable shop, or a Cobb Accessport.

 

[Apollyon12]

I ran a shorty divorced wastegate downpipe and really liked it.   With the shorty you keep the stock cat section, in the stock location, so the o2 sensors don't go haywire.    Add almost any catback and the nessesary tune and you got yourself Stage II.  

As far as intakes go, remember that the STI has the exact same one and is pulling 300hp thru it just fine.   I personally have never been impressed by any (untuned) bolt on intake.  I've driven a Mini S and a 350Z that had them and they were definitly down on low end grunt.   Maybe they made more power in the upper rpms, but changing the intake length will screw with the low end torque.   And that's what you feel driving it every day, low end umph.

The Cobb stage II does not require an intake.   You can use one with it, but it isn't needed.

 

[2point5RS_Dan]

Skip the intake.

Get whatever downpipe you want.

You will need a tune for a downpipe. Cobb access port or open source (google these).

 

[OtterCraft]

So catted versus non-catted downpipe differences or does it really not matter? I will most likely be going with the Cobb AP for tuning the turbo-back. I figured as much as far as the CAI was concerned, but always like the opinion of the people who have tried and tested different setups on the Subies.

 

[IBratmanI]

You may have an issue getting inspected at some places with a non catted down pipe. Obviously catted doesn't have quite as good flow, but it's nothing you'd notice at that kind of power level.

 

[OtterCraft]

I live in the sticks so inspection isn't a problem unless you are obvious about being safe on a road. Seems like I should save some scratch and go catless downpipe, and find a used Access Port.

 

[2point5RS_Dan]

Catless is going to be mad cheaper and if you can get around inspections you're golden....

 

[Matt]

eBay kit was cheap, cat less and stupid loud. I know a few who are running it without issue.