I have got a lot of questions about the technical side of transmission swapping my wagon. So I will explain the ways you can go about doing it with approximate budgets for each swap.
Full STi coversion , SWAP EVERYTHING
This is the route I took and I am very happy with how it turned out. I bought an entire swap kit from JDM Racing motors in spring of 2013. This included the following
- Six Speed transmission
- R180 Differential
- Driveshaft
- Control arms
- Lateral links
- Hubs
- Brembos
- Rotors
- Dust shields
- Starter
- Clutch Slave
- Clutch Kit
- Flywheel
- Axles
What I had to use from my Wrx
- Differential support girdle
- Differential mount wishbone
- ABS Sensors
- Ebrake cable
- Struts
What I had to buy new
- Group N Six Speed trans mount
- Brake Pads
- Brembo rebuild kit
- Motul Trans Fluid
- ATE Brake Fluid
It took an entire weekend to get done.
IMPORTANT
You must get a 5×100 transmission package if you want to keep your struts / 5×100 wheel setup. Brembos can also be swapped out for FHI 4 pot calipers if needed or due to budget.
Total Cost = Approximately $3900-$4000
Cheap Way
This involves running a Six speed with an automatic impreza driveshaft and R160.
What you need
- Six Speed Transmission
- Clutch kit
- Flywheel
- Automatic Impreza drive shaft
- 3.90 R160 if using JDM STi trans or 2004-2006 USDM Trans
- 3.54 R160 if using 2006+ USDM STi trans
Total Cost = Approximately $2500-$3000 depending on transmission price
The plus side is you would not have to touch the hubs , axles or other components.
The downside is that the Wrx components are weaker and are your new point of failure.
I think that covers both of the ways to do this swap , I personally always suggest doing the full swap to get the strongest possible setup so that you never have to replace differentials again.
Some pictures from my swap
– Joey
JN Garage 