BMW F30/F31 3 Series Diffusers
4 products
Every BMW F31 diffuser and F30 rear diffuser here needs the M Sport rear bumper, and the right one depends on your exhaust. Each is real carbon fiber: a wagon diffuser, a general M Sport version, a 340i diffuser and a dual-exit design for the 335i and 340i.
In the US the Sports Wagon was sold only with four-cylinder engines, so US wagon owners should start by checking the wagon and M Sport listings against their bumper. Text a photo to 609-525-4865 if you're unsure.
BMW F30/F31 3 Series Diffusers buying guide
Start with your exhaust layout
F30s and F31s left the factory with two tailpipe layouts. The six-cylinder 335i and 340i have one on each side of the bumper, while four-cylinder cars such as the 328i and 330i exit on one side only. The openings in the diffuser have to match.
- Dual-exit diffuser: for 335i and 340i sedans and wagons from 2013 to 2019. It goes on with the bolts from your original diffuser, and the listing also suggests it for owners converting an M Sport car to a dual-exit exhaust.
- 340i diffuser: for the 340i that arrived with the facelift, listed for 2015 to 2019. Predrilled holes line up with the factory bolt positions, and self-tapping screws are included.
- M Sport and wagon diffusers: the general M Sport version and the F31 Estate version don't name an engine or tailpipe layout. On a 328i, 328d or 330i, compare their photos with your bumper or text us a picture before you order.
Choosing a BMW F31 diffuser for a Sports Wagon
BMW USA sold the F31 as the 3 Series Sports Wagon, always with xDrive and a four-cylinder engine: the 328i or 328d, and later the 330i. A US wagon therefore has its tailpipes on one side unless the exhaust has been changed. Our wagon diffuser is named for the F31 Estate, the UK name for the same body, and the dual-exit diffuser lists wagons too, for cars that have been converted.
Fitting and returns
The M Sport and wagon diffusers need drilling. Their holes come predrilled, and the wagon version includes self-tapping screws. We recommend a professional installer for any of them. Test-fit before you drill: a drilled or installed part can't be returned, while one that doesn't fit the car on its product page is covered by our fitment guarantee if you contact us before installing. Pair your diffuser with the F30 side skirts or see all F30 and F31 parts.
Frequently asked questions
Will these diffusers fit an F30 without the M Sport package?
No. Every diffuser here is made for the M Sport rear bumper, and a diffuser shaped for that bumper won't fit the base one. To run one on a car without M Sport you'd first need an M Sport rear bumper. If you aren't sure which bumper your car has, text a photo of the rear to 609-525-4865.
Which diffuser suits a US-market F31 Sports Wagon?
US Sports Wagons were four-cylinder xDrive cars (328i, 328d and 330i), so the dual-exit diffuser only suits one that has been converted to a dual-exit exhaust. Look first at the F31 Estate diffuser and the general M Sport diffuser, both made for the M Sport bumper, and check their photos against your tailpipes. We're happy to confirm from a photo before you order.
Is the 340i diffuser different from the dual-exit one?
They're separate listings for the six-cylinder cars. The 340i diffuser is listed for the 340i from 2015 to 2019 and uses predrilled holes that line up with the factory bolts. The dual-exit diffuser covers the 335i and 340i from 2013 to 2019, sedan or wagon, and reuses your original bolts. A pre-facelift 335i therefore needs the dual-exit version.