Upgrade the exhaust performance and sound of your BMW G8X with the MAD S58 4" FATBOY Single Midpipe for the G80 M3, G82 M4, and G83 M4. Engineered for maximum exhaust flow and a deeper, more refined sound profile, this high-performance midpipe transforms the driving experience while maintaining excellent compatibility with both factory and aftermarket exhaust components.

The MAD FATBOY Midpipe features a full-length single 4-inch center section combined with a minimum 3-inch pipe diameter throughout the system to maintain smooth and unrestricted exhaust flow from front to rear. This optimized design reduces turbulence and back pressure while helping improve overall exhaust efficiency for enhanced performance and sound.

Designed specifically for the BMW S58-powered G8X platform, the FATBOY Midpipe delivers a deeper, more aggressive exhaust tone with significantly reduced rasp, especially when paired with aftermarket downpipes. Whether on the street or track, the system creates a clean and refined sound without excessive harshness.

For installation flexibility, the midpipe includes both 3-inch and 2.75-inch reducer couplers, allowing seamless compatibility with factory axle-back exhaust systems and most aftermarket 3-inch axle-back systems. The OEM cut location and clamp-style connection design make installation straightforward while also allowing the exhaust system to be reverted back to stock if needed.

Manufactured for precise fitment and durability, the MAD 4" FATBOY Midpipe is the ideal upgrade for enthusiasts seeking improved exhaust flow, premium sound quality, and versatile exhaust compatibility.

Features

• Designed specifically for BMW G8X M3 and M4 models
• Full-length single 4-inch center section
• Minimum 3-inch pipe diameter throughout for maximum flow
• Improves exhaust flow and reduces restriction
• Produces a deeper and more aggressive exhaust tone
• Significantly reduces unwanted exhaust rasp
• Compatible with stock and aftermarket downpipes
• Includes 3-inch and 2.75-inch reducer couplers
• Compatible with factory and most aftermarket axle-back exhaust systems
• OEM cut location for clean installation
• Clamp-style design allows reversibility to stock
• Precision-engineered for excellent fitment and durability

Important Installation Note

• Downpipe gasket is not included
• BMW Part Number Required: 18308053348
• Quantity Required: 2

Vehicle Fitment

• 2021+ BMW M3 G80
• 2021+ BMW M4 G82 Coupe
• 2021+ BMW M4 G83 Convertible

Upgrade your BMW G80 M3 or G82/G83 M4 with the MAD S58 4 Inch FATBOY Single Midpipe. Enjoy improved exhaust flow, deeper sound, reduced rasp, and premium fitment for the G8X platform.