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Discussion Starter #1
Hey guys, still new and still a million questions. My 04 STi is still stock for the most part. It has a short ram air intake i believe but no other mods and the first thing i want to do is add an exhaust. I'm looking to do a cat-back that gives me the best gains but i don't want a loud roar with it. when the car is finished i want it to sound to the casual onlooker like its obviously modded in some way but leave them wondering. more of the sleeper sound and look, that's why i decided against the VTA BOV. also i was recommended to remove the intake silencer but the intake isn't stock and the filter is just sitting in the engine bay, not attached to the intake port. would removing the silencer do anything at this point for the sound? any and all insight would be appreciated, even if its just pointing out the obvious flaws in my knowledge about cars :p
 

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I'm looking to do a cat-back that gives me the best gains but i don't want a loud roar with it.
you will not get any gains with a catback. catbacks are honestly just for noise. a turboback exhaust and a tune is where you'll see the best increase in performance.
 

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Discussion Starter #4
so if i wanted a turbo back exhaust, do they come with CATs or would it affect my emissions? Virginia laws are gay and i cant have anything that would fail emissions, also what goes into a tune? is that something that requires a shop to do?
 

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You can get the downpipe Catted or catless

Tuning can be done many ways

1) by yourself with a laptop and tatrix cable
2) handheld device such as an accessport
3) bringing it to a tuning shop
 

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so if i wanted a turbo back exhaust, do they come with CATs or would it affect my emissions? Virginia laws are gay and i cant have anything that would fail emissions, also what goes into a tune? is that something that requires a shop to do?
You can get the downpipe Catted or catless
Yes, you will fail emissions by modifying any of the stock emissions equipment with parts other than OEM. Even the catted downpipes, as Dez has suggested, will technically fail emissions. The bigger question is whether the emissions testing in your area has the means to detect these changes. Here in Maryland, emissions testing is carried out by an OBDII test wherein a technician merely plugs a scan tool into the OBDII port and checks for fault codes. Any schmuck with a tuner knows to defeat these codes, thereby "passing" emissions testing.

I suggest you do some more research and familiarize yourself with these cars before purchasing any modifications. Here is a good place to start:
Unabomber's Manifesto - NASIOC

There are far more important reasons to avoid a VTA BOV besides wanting to be a "sleeper."
 

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Go to local meets to get a feel for what exhaust looks/sounds best to you.
Buy said exhaust.
Install and enjoy.
 
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