05 impreza rs STI swap?

TrevorNoah

New member
I have a 2005 Subaru impreza 2.5 rs sedan. I'm pretty committed to car as I like the body style and no hood scoop. Just curious what all I would need to do the sti swap? I currently have stock motor and tranny wrx rear dif and axles. I'm currently working on all suspension aspects. Coilovers, tie rods, lateral links, sway bars. Next is the swap. Do I just need the sti motor and tranny and obviously bigger axles or are the wrx ones same size? Obviously ecu. Wire harness from sti? Or can I piggy back mine to sti ecu? Any information would be very helpful. New to reddit as well so please feel free inform me of anything helpful. Thank you for your time.https://scrabblewordfinder.vip/ https://www.applock.ooo/ https://www.7zip.vip/
 

Alin

Diehard Car Enthusiast!
First of all, welcome to IGOTASTI!!! You're going to absolutely love it here!! Post some pictures of your Blobeye!

Your wording is somewhat confusing. Right now, you have a "stock motor and tranny." Does this mean Impreza, WRX, or STi? "WRX rear dif and axles." I don't know exactly what you have, whether they're all from one set or if they're a combination of Impreza, WRX, and STi parts.

Here is what I know: If you want to swap in a motor from an STi, then you need the following at the minimum:

-STi complete motor assembly with TMIC and turbo
-STi ECU

Then, you have the choice of going with:

-STi complete transmission
-STi driveshaft
-STi rear differential
-STi axles, all 4 corners
-STi knuckles, hubs, Brembo's

-or-

-WRX complete transmission
-WRX driveshaft
-WRX rear differential
-WRX axles, all 4 corners
-WRX knuckles, hubs, brakes (standard or Hawkeye 4 pot)

You may have read and heard of the hybrid setups. I've seen them go both ways, too. WRX engine with STi drivetrain, or STi engine with WRX drivetrain.

Then another complication arises. It depends with what year drivetrain you choose to go with. I think almost all GD STi models vary in some aspect, with 2004 being the biggest outlier. WRX drivetrains differ as well between the 2002-2007 models.

There's a lot of research you need to do regarding the internals of the transmissions and differentials.

I left out the suspension because they can be either mixed and matched from various stock vehicles, or you can just go all out aftermarket with the endless selections.

So, what model year STi motor are you contemplating? What year WRX or STi drivetrain are you contemplating?

Also, if you're going to keep the hood scoopless look, I'm assuming you've planned out a FMIC as well?
 

Grinder34

Track Monkey
As was mentioned: with no hood scoop you cant do TMIC, so you'll need a full FMIC setup.

Do you already have a donor STI?
 

Batmobile_Engage

Squirrel Meat Aficionado.
Staff member
I definitely do not want to kill your dreams. With enough motivation and money, you can accomplish anything. That said, I think you would be better off trying to find a used 2006-ish STi to build up. Especially if your 2.5 RS is in good shape and running well, I'd kind of hate to take that kind of reliability off the road and butcher it. Then again, I don't know what kind of resources you are working with. But if it were me, I'd probably daily drive the 2.5 RS and find an STi to build up.
 

Eagleye

Tinkerer
I definitely do not want to kill your dreams. With enough motivation and money, you can accomplish anything. That said, I think you would be better off trying to find a used 2006-ish STi to build up. Especially if your 2.5 RS is in good shape and running well, I'd kind of hate to take that kind of reliability off the road and butcher it. Then again, I don't know what kind of resources you are working with. But if it were me, I'd probably daily drive the 2.5 RS and find an STi to build up.

This^^^
 
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