Takumi Project Rear Diffuser for WRX STI (VAB) / WRX S4 (VAG) / GR86 (ZN8) / BRZ (ZD8) [Carbon/FRP]
Efficiently covers the area beneath the trunk, where airflow is most turbulent. Despite its compact design, it generates significant downforce. Installation is a simple bolt-on process, and the design is largely unaffected by the configuration of the subframe or exhaust system. An FRP version offering excellent cost-performance is also available.

A functional design that efficiently covers key areas prone to turbulence
The Takumi Project diffuser features a simple, one-piece design. It extends further than the factory-installed rear bumper diffuser—covering the area beneath the trunk—to deliver effective airflow management.
Crafted from high-quality carbon fiber (CFRP), it showcases exceptional workmanship. Its beauty and finish are so exquisite that it almost feels a shame to mount it on the underbody, where it remains largely out of sight.
It is remarkably lightweight, weighing in at just 1.945 kg, ensuring that any increase in vehicle weight is kept to a minimum.
Fins smooth the airflow, while the upturned rear edge increases flow velocity

The plate suppresses turbulence, and the fins straighten the airflow. The upturned rear edge then accelerates the airflow, generating negative pressure to produce downforce. The Takumi Project diffuser was developed with a focus on achieving these fundamental functions with maximum efficiency.

The airflow fins are designed with ground clearance and parking curbs in mind, so there is no need to worry about compromising your vehicle’s everyday usability.

A special coating on the underside maintains its appearance by preventing dust buildup
A common drawback of carbon fiber diffusers is that dust and dirt tend to accumulate in the weave on the underside (the side facing the vehicle body).

The Takumi Project carbon diffuser features a special coating on this surface to prevent dust adhesion. It resists dirt buildup, making cleanup quick and easy during car washes.

Bolt-on installation using dedicated brackets—no drilling required

Installation is quick and straightforward using the included dedicated brackets.

Since it utilizes existing bolt holes, no drilling or modification is required, ensuring no damage to your vehicle.

It is compatible with a wide range of muffler models, including factory exhausts, and supports mounting configurations for most vehicle specifications. * Compatibility has not been confirmed for some mufflers, and others may require minor modifications for installation.
* Installation on vehicles equipped with an AVO center pipe is generally not supported.
* Please refer to the “Notes” section at the end for details regarding compatibility.

Note 1: If an STI rear under-spoiler is installed, it must be removed.

Note 2: Compatibility with rear member setups other than the standard specification…

<Confirmed Specifications>

・Vehicles equipped with STI Flexible Support Subframe
→ Installation is possible using the included machined aluminum collars and long bolts.

・Vehicles equipped with Cusco Power Brace Rear Member
・Vehicles equipped with LAILE Rear Member Support Bar
→ Installation is possible using dedicated machined aluminum collars and long bolts. Please inform us of this when placing your order.

*Reference link for LAILE Rear Member Support Bar installation:
https://cartune.me/notes/kolk3YkfxI

・Compatibility with other specifications has not yet been confirmed; however, please contact us, and we will verify and get back to you.
Please feel free to contact us if you are considering installation with specifications other than those from OEM, STI, Cusco, or LAILE.

Note 3: Muffler compatibility…

<Confirmed mufflers that can be installed without modification>

・OEM muffler
・HKS Super Turbo Muffler
・STI Performance Muffler
・STI Exhaust Kit
・Kakimoto Kai Regu.06 & R (Dual-exit with center pipe)
・Kakimoto Kai Class KR (Dual-exit with center pipe)
・Takumi Project “Kiwami” Full Titanium Muffler
・Trust Power Extreme R DD
・Trust Power Extreme R HD *Compatibility confirmed August 2022
・Fujitsubo Authorize RM Muffler *Compatibility confirmed June 2022
・GP Sports EXAS EVO Tune – Single Exit (Left Side) (Part No. 252607) *Compatibility confirmed November 2022
*Dual-exit version (Part No. 252605) is not compatible.・TOMEI Titanium Muffler *Compatibility confirmed as of February 2023

<Mufflers confirmed to require modification>

・HKS Hi-Power SPEC-L Muffler
・Kiwami Full Titanium Muffler (Dual-exit)

<Incompatible mufflers>

・GP SPORTS EXAS EVO Tune (Left/Right exit) (Part No. 252605)
*Confirmed incompatible as of August 2022

Note 4. Regarding mid-pipe specifications…

For vehicles equipped with an AVO center pipe, installation without modification is not possible, even if the muffler model is otherwise compatible.
Please note that installation is generally not possible in this configuration.

<Rear bumpers confirmed for installation>

For ROWEN rear bumpers, a separate bracket or
spacers and long bolts (M6) are required.