Milltek Non-Resonated Secondary Cat Bypass | BMW G8X M3 M4

Description

The Milltek Axle Back Non-Resonated Secondary Cat Bypass is engineered for BMW G8X M3 and M4 models. This system replaces the secondary catalyst and is designed to fit OEM downpipes and Milltek Axle Back systems only. Direct factory fitment requires no modification. Constructed from T304L stainless steel with mandrel-bent 3.00" (76.20mm) primary piping, the non-resonated design eliminates resonance points in the mid-range for a pronounced, race-focused tone. Hand-finished welds and CNC-formed flanges ensure OEM+ build quality. Decibel-tested for full-throttle character without excessive drone at cruise. Fitment & Compatibility • BMW M3 G80 (S58 engine) • BMW M4 G82 (S58 engine) • Fits OEM downpipes only • Compatible with Milltek Axle Back cat-back systems • Direct bolt-on installation with OEM hangers This secondary cat bypass delivers the engineering precision and material integrity expected from the brand—not a universal-fit compromise. Designed and manufactured in the UK with 40+ years of performance exhaust heritage. Tested at the Nurburgring.

Fits 14 vehicles including:

• 2021 BMW M3— G80 M3 & M3 Competition S58 3.0 Turbo > 2021 and Later
• 2022 BMW M3— G80 M3 & M3 Competition S58 3.0 Turbo > 2021 and Later
• 2023 BMW M3— G80 M3 & M3 Competition S58 3.0 Turbo > 2021 and Later
• 2024 BMW M3— G80 M3 & M3 Competition S58 3.0 Turbo > 2021 and Later
• 2025 BMW M3— G80 M3 & M3 Competition S58 3.0 Turbo > 2021 and Later
• 2026 BMW M3— G80 M3 & M3 Competition S58 3.0 Turbo > 2021 and Later
• + 8 more vehicles