BMW B58 Gen 1 5" Inch Catless Decat Downpipe – M140i, M240i, 340i, 440i, 540i + More
£209.99
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BMW B58 Gen 1 5" Inch Catless Decat Downpipe – M140i, M240i, 340i, 440i, 540i + More
£209.99
SB Custom — Exhaust Downpipes · Gen 1 B58
BMW B58 Gen 1 5" Catless Decat Downpipe
A high-flow 5-inch catless decat downpipe for Gen 1 B58-powered BMWs. Built for real performance gains — maximum exhaust flow, faster turbo spool, more power, and a noticeably more aggressive exhaust tone — a straight bolt-on replacement for the restrictive factory unit.
5-INCHBore Size
T304 STAINLESSMaterial
CATLESS / DECATStyle
1 YEARWarranty
Key Features
- Significantly increased exhaust flow for real performance gains
- Fits both OPF and Non-OPF cars
- High-grade stainless steel construction with hand TIG-welded joints
- Direct bolt-on replacement for the restrictive factory downpipe
- Exact fitment for Gen 1 B58-equipped BMW models, 2015–2019
- 1 year warranty against manufacturing defects and premature failure — no quibble replacement
Compatible Vehicles
1 Series
F20 / F21 M140i (2016–2019)
2 Series
F22 / F23 M240i / M240i xDrive (2016–2021)
3 Series
F30 / F31 340i / 340i xDrive (2016–2018)F34 340i GT (2016–2018)
4 Series
F32 / F33 / F36 440i / 440i xDrive (2016–2019)
5 Series
G30 / G31 540i / 540i xDrive — Pre-LCI (2017–2019)
6 Series
G32 640i GT — Pre-LCI
7 Series
G11 / G12 740i / 740Li — Pre-LCI (2016–2019)
X Series SUVs
G01 X3 M40i — Pre-LCI (2018–2019)G02 X4 M40i (2019)
Please note: This downpipe is designed for Gen 1 B58 (B58B30M0 / B58A) "F-Chassis" and early "G-Chassis" models, built before Technical Update 1 (Gen 2). Please check your chassis code before ordering if you're unsure which generation you have.
TIG-Welded Stainless
High-grade stainless steel, hand TIG-welded for a durable, leak-free joint.
UK Stock, Fast Delivery
Dispatched from the UK — no long waits on overseas shipping.
Secure Packaging
Reinforced packaging designed to prevent transit damage.
Dedicated UK Support
Fitment questions or issues? Our team is on hand to help.
What's in the Box
- 1 x 5-inch catless decat downpipe (Gen 1 B58)
Ready to unlock your Gen 1 B58's full potential? Real performance gains, fit and forget, backed by our 1 year warranty.
This downpipe removes the OEM catalytic converter, so exhaust emissions will no longer meet original factory standards. It's intended for off-road, track, or motorsport use — please check your local emissions and road-legality regulations before fitting to a vehicle used on public roads. Fittings and gaskets are not included.