Milltek Sport Catted & Catless Downpipes - 2021+ BMW 4 Series G82 M4 & M4 Competition S58 3.0 Turbo

Milltek Sport catted and catless downpipes, cat pipes and front pipes for the BMW 4 Series G82 M4 & M4 Competition S58 3.0 Turbo (2021+). These parts open up the hot side of the exhaust, cut backpressure and sharpen throttle response. Pick the option that matches your exhaust: some are built to fit a Milltek cat-back, others bolt to the stock cat-back.

Compare every part number

"Race/Track only" and "Stage 2 ECU remap" are shown only where Milltek states them. A dash means Milltek does not state it for that part.

What comes with each part number

• SSXBM1333 (Large Bore Downpipe and Hi-Flow Sports Cat): 1 x LH Cat Downpipe; 1 x RH Cat Downpipe
• SSXBM1235 (Large Bore Downpipe and Hi-Flow Sports Cat): 1 x LH Downpipe & Cat Assembly; 1 x RH Downpipe & Cat Assembly; 1 x LH Cat Link Pipe Milltek note: with HJS HQ 200CPSI Cats (No CEL or ECU Software Required) - Fits to OE Secondary Cats & Milltek Sport Cat Back System.
• SSXBM1271 (Large-bore Catless Downpipe): 1 x LH Primary Cat Bypass; 1 x RH Primary Cat Bypass; 1 x LH Cat Link Pipe Milltek note: Requires Stage 2 ECU Remap - Fits to OE and Milltek Sport Systems.
• SSXBM1334 (Large-bore Catted Downpipe Bypass Pipes): 1 x LH Cat Replacement Downpipe; 1 x RH Cat Replacement Downpipe
• SSXBM1270 (Secondary Catalyst Bypass): 1 x LH Silencer Replacement Pipe; 1 x LH Secondary Cat Bypass; 1 x RH Secondary Cat Bypass; 1 x RH Silencer Replacement Pipe; 1 x Chassis Brace Plate; 2 x Adapters to OE System Milltek note: Secondary Cat Bypass - Non Resonated - Fits to OE Downpipes & Axle Back System Only - Requires OE system to be cut.
• SSXBM1339 (Secondary Catalyst Bypass): 1 x 102MM / 4" Single Mid Pipe (Non-OPF Cars); 1 x LH Silencer Replacement Pipe; 1 x RH Silencer Replacement Pipe; 1 x Chassis Brace Plate; 2 x Adapters to OE System
• SSXBM1268 (Secondary Catalyst Bypass): 1 x LH Silencer Replacement Pipe; 1 x LH Secondary Cat Bypass; 1 x RH Secondary Cat Bypass; 1 x RH Silencer Replacement Pipe; 1 x Chassis Brace Plate; 2 x Adapter to Milltek Sport System
• SSXBM1340 (Secondary Catalyst Bypass): 1 x 102MM / 4" Single Mid Pipe (Non-OPF Cars); 1 x LH Silencer Replacement Pipe; 1 x RH Silencer Replacement Pipe; 1 x Chassis Brace Plate; 2 x Adapter to Milltek Sport System
• SSXBM1342 (Secondary Catalyst Bypass): 1 x 102MM / 4" Single Mid Pipe (Non-OPF Cars); 1 x X Pipe; 1 x Chassis Brace Plate; 2 x Adapters to OE System
• SSXBM1341 (Secondary Catalyst Bypass): 1 x 102MM / 4" Single Mid Pipe (Non-OPF Cars); 1 x X Pipe; 1 x Chassis Brace Plate; 2 x Adapter to Milltek Sport System
• SSXBM1269 (Secondary Catalyst Bypass): 1 x Centre Silencer; 1 x LH Secondary Cat Bypass; 1 x RH Secondary Cat Bypass; 1 x Chassis Brace Plate; 2 x Adapters to OE System Milltek note: Secondary Cat Bypass - Resonated - Fits to OE Downpipes & Axle Back System Only - Requires OE system to be cut.
• SSXBM1267 (Secondary Catalyst Bypass): 1 x Centre Silencer; 1 x LH Secondary Cat Bypass; 1 x RH Secondary Cat Bypass; 1 x Chassis Brace Plate; 2 x Adapter to Milltek Sport System

Catted and catless downpipes

A catted downpipe keeps a catalytic converter in the downpipe. A catless downpipe (de-cat) replaces it with a straight pipe. Each option name above says which one it is.

Fitment

BMW 4 Series G82 M4 & M4 Competition S58 3.0 Turbo, 2021+. US-market model listing. Confirm your exact model, engine and options before ordering.

About Milltek Sport

• T304L stainless steel, CNC mandrel bent.
• Designed and developed in Derby, UK with a US facility in Knoxville, Tennessee, and tested at the Nürburgring.
• Company founded in 1983.

Warranty

Milltek covers most products with a lifetime guarantee. Downpipes, hi-flow catalysts and any part with valves are covered for 2 years or 80,000 km, and electronic products for 2 years. Claims go through the authorized dealer you bought from, and cover the original purchaser only. Full terms: millteksport.com/Warranty.html

Notes

• Some options need a Stage 2 ECU remap. Read the option name before you order.
• Catless downpipes and other cat bypass parts replace emissions equipment. They are sold for off-road and competition use where local law allows. You are responsible for checking the rules that apply to your vehicle.
• Fitting times are Milltek estimates for a professional installer.