Upgrade your 2025+ BMW M340 M440 with the MAD BMW B58 Gen 3 "Fat Boy" 5.0" Catless Downpipe—the ultimate performance upgrade designed to unleash the full potential of your engine. Crafted from premium-quality 304 stainless steel, this larger-diameter 5.0-inch downpipe offers superior airflow, delivering enhanced horsepower, quicker turbo response, and noticeable torque gains. The increased diameter of the "Fat Boy" downpipe sets it apart from our standard catless models by providing a deeper, richer, and significantly more aggressive exhaust tone. Precision-engineered welds and exceptional craftsmanship ensure perfect fitment, durability, and peak performance for enthusiasts demanding maximum results. Transform your BMW M340's driving experience by choosing MAD's top-tier downpipe, designed specifically for drivers seeking ultimate airflow and a sound profile that commands attention. Features: Premium 304 stainless steel for superior durability Expanded 5.0-inch diameter for unmatched airflow and performance Deeper, richer, and more aggressive exhaust tone Improved horsepower and torque compared to standard catless downpipes Precision craftsmanship and perfect bolt-on fitment Ideal for high-performance builds and enthusiasts seeking maximum results Fitment: 2025+ BMW M340 2025+ BMW M440 2025+ BMW X3 G45 M50 2025+ BMW X4 G46 M50   Emissions Disclaimer:This product is not legal for sale or use on pollution-controlled vehicles operated on public roads, highways, or streets. It is intended for off-road, race, or closed-course competition use only, where such modifications are permitted. By purchasing this product, you acknowledge and agree that: You are responsible for compliance with all applicable emissions laws and regulations. MAD and its affiliates disclaim any liability for improper or unlawful use of this product. Use of this part on public roads may violate the Federal Clean Air Act (42 U.S.C. § 7522) and similar state laws. Please check your local laws before purchase and installation.