CarBahn Stainless Steel High-Flow Exhaust System – BMW M340i / M440i (Cat-Back)
Unlock the full potential of your BMW M340i or M440i with the CarBahn Stainless Steel High-Flow Exhaust System — a true cat-back upgrade engineered to deliver the ideal mix of motorsport character and daily-driver refinement. Designed and specified by Steve Dinan and the CarBahn engineering team, this system reflects decades of tuning experience and an uncompromising commitment to OEM-level quality.
Crafted entirely from corrosion-resistant 304 stainless steel with a clean brushed finish, the CarBahn exhaust is built to withstand years of heat cycles, weather exposure, and hard driving without rusting or discoloration. Unlike basic axle-back muffler swaps, this is a complete cat-back system engineered to improve exhaust flow, reduce backpressure, and bring out the true sound and responsiveness of BMW’s turbocharged inline-six.
The result is a deep, powerful exhaust note that wakes up under throttle — aggressive when you want it, composed when you don’t. Cruising remains smooth and drone-free, making this system just as rewarding on a road trip as it is on a backroad pull.
Engineered Fitment — Not Generic Overseas Hardware
CarBahn systems aren’t mass-produced, one-size-fits-all imports. This exhaust is built to CarBahn-specified design standards, offering superior fitment and consistency compared to many overseas alternatives. Every detail is engineered for a tight, precise installation — from the alignment to the sealing surfaces — ensuring the system performs like an OEM component, not an aftermarket compromise.
Premium Hardware and Quiet Precision
Key upgrades include OEM-quality clamps and an advanced exhaust flapper valve design that uses a high-tech anti-rattle spring, dramatically reducing unwanted noise and vibration. The system also incorporates a joggle-slot connection, improving sealing at the joints and preventing the small leaks that can plague lower-quality exhaust setups.
Key Features:
- CarBahn-specified design, engineered by Steve Dinan for the B58 platform
- Full stainless steel cat-back construction — not just mufflers — for real performance improvement
- Brushed 304 stainless finish for long-term durability and premium appearance
- Improved fitment and quality compared to overseas-manufactured alternatives
- Joggle-slot joint design for superior sealing and connection integrity
- OEM-quality clamps for factory-level installation and longevity
- Upgraded exhaust flapper valve with anti-rattle spring technology for reduced noise
- Aggressive yet refined sound with zero drone during highway cruising
- Direct bolt-on fitment for BMW M340i and M440i models
- 2-year unlimited mileage parts warranty
- USA-based support from the CarBahn team
Elevate your BMW’s sound, performance, and character with an exhaust system designed to do more than just turn heads — it’s engineered to make every drive feel sharper, louder, and more alive… the way Steve Dinan intended.