The MAD BMW M340 / M440 Axle Back Exhaust System is designed to deliver a bold sound upgrade without unnecessary parts or added cost. Unlike our previous full catback design, this updated version is more cost-effective, easier to install, and focuses only on the section of the exhaust that actually changes sound and driving experience.
On the M340i and M440i platform, a full catback simply is not needed. The factory midpipe is already a straight-through, non-restrictive design with no cats or resonators, meaning there is little to no performance or sound benefit from replacing it.
This axle back system provides a deeper, more aggressive tone under throttle while remaining refined and comfortable during normal driving. It also upgrades the factory single-valve setup into a true dual M-style valve configuration using the OEM valve motor along with an additional included valve and harness. The exhaust continues to function perfectly with OEM drive modes, staying quiet in Comfort and fully opening in Sport.
Installation is quick and straightforward using OEM BMW designated cut points, allowing the car to easily be returned to stock later using OEM BMW sleeve clamps. Part #'s 18307560781 & 18307560780
Constructed from premium 304L stainless steel, the system is available with brushed stainless, black, or carbon tips.
Features:
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More cost-effective and easier to install than our previous catback system
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Aggressive sound improvement while retaining the factory midpipe
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True dual M-style valve setup with included valve motor and harness
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Retains OEM drive mode functionality
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Premium 304L stainless steel construction
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Choice of brushed stainless, black, or carbon tips
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Cut-and-clamp installation using OEM BMW cut points
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Easy return to stock if needed
Fitment Includes:
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BMW M340i G20 2018+
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BMW M440i G22 Coupe 2018+
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BMW M440i G26 Gran Coupe 2021+
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BMW M340i / M440i 2025+
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Compatible with RWD and xDrive models
