BMW G80 G81 M3 & G82 G83 M4 Pre-Preg Carbon Fibre Rear Diffuser by FORM

Engineered from the outset to amplify the already bold backend on the G80 and G82 platform, this pre-preg carbon fibre diffuser is the perfect pairing to add even more presence to your car. Forge Automotive supplies this diffuser and can fit it at our Darwen and Leeds sites.

Made in pre-preg carbon fibre to ensure perfect fitment and durability, the 2x2 weave matches any OEM carbon you may already have on your car. Want the full carbon kit? Pair with a FORM Industries Rear Spoiler and front splitter.

FORM Industries have developed this product to retain all the OEM mounting points, just as the original diffuser does. This has been done using advanced 3D CAD.

Key features

• Rear diffuser in OEM style
• Pre-preg dry carbon fibre, 2x2 weave to match OEM carbon
• Retains all OEM mounting points, developed from 3D CAD

What's in the box

• 1 x pre-preg carbon fibre rear diffuser

Fitment

• BMW M3 Saloon (2020+, G80)
• BMW M3 Touring (2022+ G81)
• BMW M4 Coupe (2020-2024, G82 Pre-LCI)
• BMW M4 Coupe (2024+, G82 LCI)
• BMW M4 Convertible (2020-2024, G83 Pre-LCI)
• BMW M4 Convertible (2024+, G83 LCI)

Supplied, fitted and finished by Forge Automotive

Forge Automotive can fit this diffuser at either of our sites: Darwen in the North West or Gildersome, Leeds in Yorkshire. Forge Automotive can also finish this diffuser before fitting: paint protection film (PPF) to guard the carbon, a colour change or satin wrap, or colour matching to the car. Ask when ordering. See more BMW M3 G80/G81 parts.

Common questions

What is pre-preg carbon fibre?
Pre-preg is carbon cloth that arrives from the mill already impregnated with a measured amount of resin. The part is laid up in the mould and cured under heat and pressure, usually in an autoclave or oven. Because the resin content is controlled, the finished part is lighter, stiffer and more consistent than a hand-laid one, with a cleaner weave and better dimensional accuracy. It costs more to make, which is why pre-preg parts sit at the top of a range.

What does "dry carbon" mean?
Dry carbon is the everyday name for a pre-preg part: carbon fibre all the way through, rather than a carbon skin over a fibreglass or plastic base. The surface still has a clear lacquer, but there is no excess resin in the laminate, so the part is light and rigid.

What is a 2x2 twill weave?
The weave pattern in the carbon cloth. In a 2x2 twill each strand passes over two and under two, which gives the diagonal pattern BMW use on their own M Performance and M carbon parts. Choosing 2x2 means aftermarket and factory carbon on the same car match.

How do I look after a carbon fibre part?
Treat the lacquer like paint: wash with pH-neutral shampoo, avoid harsh solvents, and wax or seal it. UV is what ages carbon, so a protected finish lasts longer. Forge Automotive can apply paint protection film to any carbon part before fitting, which guards against stone chips and keeps the weave clear.

Is it a direct replacement?
Yes. FORM state it retains all the OEM mounting points of the original diffuser.

Fitting is available on every part at our North West (Darwen) and Yorkshire (Leeds) workshops. Prefer to fit it yourself? Fitting instructions ship with every part.

In-stock parts ship in 3–5 working days, fully insured. Every part is fitment-checked before dispatch.

Covered by the manufacturer warranty. Fitting through our workshop keeps it intact.