WRX Six-Speed Swap Guide: STi 6MT Compatibility Checklist by Chassis Year

October 12, 2026

⚠️ Important Disclaimer: Exact fitment requirements vary by individual chassis, drivetrain configuration, and build history. This guide is a general reference only. Always verify compatibility with a qualified Subaru specialist before purchasing or installing any components.

Why Swap to the STi Six-Speed?

The Subaru USDM STi's gearbox is the most sought-after upgrades for WRX owners. It offers tighter gear spacing, stronger internals rated for higher torque, and access to the STi's Driver-Controlled Centre Differential (DCCD) system — a game changer for AWD balance on both street and track. The swap is physically possible across most 2002–2014 WRX’s but the parts list can vary based on budget and availability.

Requirements (All Years)

Regardless of your WRX generation, every STi six-speed swap requires attention to these core components:

Clutch & Flywheel: The 06-13 stock WRX clutch is incompatible with the STi 6MT input shaft. You will need an STi-spec clutch kit and a matched flywheel. We typically stock aftermarket clutch kits.
Driveshaft-to-Differential Bolt Set: The driveshaft flange bolt pattern must match. This is why the “ poor mans swap “ uses an automatic driveshaft. When doing a full swap, you use the STi oem driveshaft.
DCCD Control Unit: The STi six-speed routes signals through the DCCD system. When swapped into a wrx , most leave it unhooked to start with , which leaves the center diff “ open “. A aftermarket controller can be added to let you select the amount of power being sent to the rear wheels ( I wire ect , sold separately unless specificly indicated)
VSS ( vehicle speed sensor ) 2002-2007 wrx and STi have a sensor in the front diff housing that provides the signal for the speedometer.
08 up cars pick the signal up from the front abs sensor. I wire makes the vss converter ( sold separately unless noted ) that allows the use of the heavily available 08-21 STi six speeds into the 02-07 cars , allowing them to have a working speedometer

Chassis-Specific Checklist

🚗 2002–2005 WRX (Bugeye / Blobeye)

This generation presents the most involved swap due to differences in the rear differential, driveshaft length, and tunnel dimensions compared to the STi donor car.

Rear Differential: The 02–14 WRX uses an R160 rear diff. The ratio for rear differential final drive for 2002 - 2005 wrx is 3.54 , 2006-2007 wrx is 3.7 and 08-14 wrx is 3.9 . 2004 and 2005 USDM have a R 180 with 3.9 FD and 06-21 usdm STi use a r180 with a final drive of 3.54. 06 + STi six-speed is tuned around the larger R180 diff with a 3.54 final drive ratio.
Driveshaft: The WRX driveshaft is a different length from the STi unit, and has a smaller rear flange mounting pattern. When doing a complete swap , a STi one is used. You can also mix and match with a r160 and a combination of oem parts to achieve a “ poor mans swap “
Flywheel (02–05 specific): The XClutch Chromoly Flywheel for 2002–2005 WRX / Forester XT / Baja Turbo is designed for this chassis's crank flange specs.
Shifter & Console: The 02–05 shifter tunnel requires the correct shifter bracket. The OEM Shifter Boot Bezel Trim (2002–2004 WRX) fits the early console. An STi six-speed shifter and bracket assembly will need to be sourced to match the 6MT shift tower location.
Transmission: For reference, we have a 2002–2004 WRX EJ205 5-Speed Transmission (3.54 AWD) in stock — useful as a core trade or for those retaining the 5MT.

🚗 2006–2007 WRX (Hawkeye)

The Hawkeye WRX shares more dimensional similarities with the 2004–2007 STi, making this one of the more straightforward swap generations. However, several key parts still differ.

Driveshaft: The 06–07 WRX OEM driveshaft is a 5-speed unit and will not work with the STi six-speed output flange. See the 2006–2007 WRX OEM Driveshaft Assembly (5MT) for reference/core. An STi-spec driveshaft is required for the swap.
Shifter Bracket & Console: Use the OEM Shifter Bracket (2004–2007 WRX STi) to properly locate the STi shift tower. The 2005–2007 WRX Shifter Boot Bezel Trim and 2005–2007 STi Center Console Vent/Shifter Trim are needed for a clean interior finish.
Rear Differential Temperature Sensor: The STi R180 differential uses a temperature sensor not found on WRX models. The 2004–2007 STi R180 Rear Differential Temperature Sensor should be included in your build.
STi Shift Knob: The 6MT uses a different shift pattern. The OEM STi 6MT Shift Knob completes the interior conversion.

🚗 2008–2014 WRX (GH/GR/GV Chassis)

The 2008+ WRX received significant platform changes. While the engine bay is more spacious, the transmission tunnel, rear subframe, and electrical architecture differ from earlier cars and from the GR STi donor.

Rear Differential Mount & Crossmember: The 08–14 WRX rear subframe geometry differs from the STi. The 2008–2014 WRX Rear OEM Diff Mount Brace is often reused or upgraded. The 2015–2021 STi Rear Differential Crossmember with Studs is listed for reference — confirm whether your chassis accepts it before purchasing.
Shifter Console & Trim: The 08–14 interior requires the matching STi shifter tower and surrounding trim. We stock the 2008–2014 WRX STi OEM Center Shifter Console, Center Shifter Console (variant B), Shifter Cover Trim, Shifter Cover Trim (variant B), and the Center Shifter Console Sticker.
Shifter Boot: The 2008–2021 WRX STi OEM Manual E-brake Shifter Boot (A), (B), and (C) are available — check condition and connector routing for your specific build.
Short Throw Shifter: If you want to improve the six-speed's already-short throw, the COBB Short Throw Shifter with Bushings (2008–2021 STi) is a popular addition.
5-Speed Shifter (Core/Reference): The 2008–2014 WRX 5-Speed COBB Short Shifter Assembly is listed for those retaining the 5MT or using it as a core.

Professional Fitment Verification — Strongly Recommended

This guide is designed to give you a head start on sourcing parts, but a six-speed swap involves driveline geometry, ECU calibration, wiring harness adaptation, and AWD torque split settings that are unique to every build. We strongly recommend having your specific vehicle assessed by a qualified Subaru performance shop before finalizing your parts list. Mismatched differentials, incorrect driveshaft lengths, or an unconfigured DCCD can cause driveline damage or unpredictable handling.

Need Help Finding a Part?

Our inventory turns frequently. If you don't see a specific part listed above, use the search bar or contact us — we may have it in stock or be able to source it. New OEM pull inventory is added regularly.

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