BMW G80 M3 & G82/G83 M4 3-Piece Rear Diffuser D3 – Prepreg Dry Carbon Fiber (Unitexclusives)

We designed the D3 to finish the rear of the BMW G80 M3 and G82 M4 from corner to corner. It is a 3-piece diffuser in prepreg dry carbon: a center section that boxes in the quad tailpipes, and two corner extensions that run out toward the rear wheels.

As seen on the Anotherpull YouTube channel, fitted to a G80 M3.

The look

From behind, the D3 turns the base of the bumper into one broad carbon band. Each pair of tailpipes sits in its own deep, squared-off box with clipped corners, and short vertical fins hang between the two boxes.

At each end, a slim blade leaves the center section and runs under the bumper corner to the wheel arch, so in profile a low, dark line follows the base of the car.

The twill weave sits under a gloss finish. On the bright green M3 Competition in our photos the carbon reads almost black under loud paint; on a dark blue-violet car the weave shows where light hits the box rims.

Made for the M3 and M4

The G80 M3 sedan and G82 M4 coupe share the S58 twin-turbo inline-six, with 473 hp in base form and 503 hp as a Competition at launch. At the back, every car gets a black diffuser framing two pairs of 100 mm tailpipes.

Gloss-black lower bumper pieces and side sills wrap a dark band around the car; the D3 carries that band to the corners in exposed carbon.

Why this one

BMW’s own carbon rear diffuser, M Performance part 51128075031, is one center piece; its carbon end winglets are a separate set, different for the M3 and the M4. The D3 includes the center and both corner extensions for well under the price of BMW’s diffuser alone.

Cheaper diffusers are often wet carbon, which can yellow or warp in the sun, or fiberglass hidden between carbon layers. The D3 is prepreg dry carbon, in a shape of our own.

Highlights

• Three pieces. A center diffuser and two rear corner extensions, drawn as one set.
• Boxed tailpipes. Each pair of tips sits in its own clipped-corner carbon frame.
• Prepreg dry carbon. A twill weave under a gloss finish.
• Factory mounting points. No cutting and no changes to the car.
• Our own design. Shaped in-house at UNIT 17 Auto Styling, not copied from a BMW part.

Living with it

The corner extensions form the lowest edge of the bumper corners, so take steep ramps and driveway exits slowly and at an angle, especially if the car is lowered.

Nothing is cut or drilled, so the factory diffuser can go back on later.

Check before you buy

• Choose M3 or M4 in the options: the two cars’ rear bumpers differ, and each version fits one.
• The M3 CS, M4 CS and M4 CSL come with their own factory carbon rear diffuser. Check with us before ordering for one.

Installation

• Mounting. The factory mounting points
• Drilling. None, and no cutting
• Removable. Yes
• In the box. Center diffuser (1) and rear corner extensions (2)

Good to know

• The green M3 in our photos also wears a large carbon rear wing, aftermarket wheels and body-color lower bumper corners. None of these come with the D3, nor do the exhaust tips.