$595.00 USD
$595.00 USD










The MAD BMW G87 M2 4" Fat Boy Midpipe is engineered to deliver maximum performance and a refined yet aggressive exhaust note for the S58-powered G87 M2. Designed for enthusiasts who demand optimal flow, this midpipe features a full-length 4" center section with a minimum 3" diameter throughout, eliminating restrictions and improving throttle response.
The midpipe produces a deeper, smoother, and more aggressive tone with noticeably less rasp, even when paired with aftermarket downpipes. Ideal for both track performance and street driving, it enhances your vehicle’s sound without compromising drivability.
Installation is simple and reversible thanks to the factory cut point and clamp system. The kit includes 3" and 2.75" reducer couplers to ensure compatibility with both factory and aftermarket axle-back exhaust systems. An upgraded brace is also included for proper clearance with the larger 4" midpipe.
Key Features:
• Full-length 4" center section for maximum exhaust flow
• Minimum 3" diameter throughout for unrestricted performance
• Deep, aggressive exhaust tone with reduced rasp
• Compatible with stock and aftermarket downpipes
• Includes 3" and 2.75" reducer couplers for axle-back compatibility
• Factory cut point and clamp system for easy, reversible installation
• Upgraded brace for proper clearance and fitment
Fitment:
• BMW G87 M2 with S58 engine
Transform your G87 M2’s exhaust performance and sound with the MAD 4" Fat Boy Midpipe—precision-engineered for power, clarity, and track-ready aggression
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$595.00 USD
$595.00 USD
This product can expose you to chemicals such as lead and lead compounds, which are known to the State of California to cause cancer or birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov.
For a complete list of chemicals known to cause harm, visit https://www.p65warnings.ca.gov/chemicals.
Under the federal Clean Air Act (42 U.S.C. §7522(a)(3)), it is illegal to manufacture, sell, install, or use any part that defeats or alters a motor vehicle’s emission control system for use on public roads. Unless a product has received an Executive Order (EO) from the California Air Resources Board (CARB), it is not legal for use or installation on any pollution-controlled vehicle driven on public highways.
Some states have CARB-equivalent or independent emissions laws. Customers are responsible for verifying local regulations before purchasing or installing emissions-related products.
All performance, racing, or competition parts sold by this company are intended solely for off-road, closed-course, or competition use on vehicles that are never registered or used on public highways.
Kies Motorsports, LLC sells and markets these products for lawful use only. We do not condone or authorize the use of emission-control defeat devices or any modification that violates the Clean Air Act or state regulations.