Meet the MAD B58 Fat Boy 5'' catless downpipe. The MAD 5 inch Catless B58 Downpipe is a high-performance aftermarket upgrade for BMW B58 engine vehicles, designed to increase power and torque while improving exhaust flow. This downpipe is made from premium quality stainless steel and is precision-engineered to fit perfectly with the stock exhaust system, ensuring a seamless installation process. With a 5 inch diameter, this downpipe provides unrestricted exhaust flow, which reduces backpressure and increases horsepower and torque output. It also features a catless design, which eliminates the factory catalytic converter for even more performance gains. This makes it an ideal choice for car enthusiasts who are looking to improve the performance and sound of their BMW B58 engine vehicles. The MAD 5 inch Catless B58 Downpipe is designed to withstand the high temperatures and pressures of high-performance driving, ensuring reliable performance for years to come.  Installation of the MAD 5 inch Catless B58 Downpipe is straightforward and can be completed with basic hand tools. Overall, if you're looking to improve the performance and sound of your BMW B58 engine vehicle, the MAD 5 inch Catless B58 Downpipe is a must-have upgrade. It delivers significant performance gains while also adding a much needed sound improvment. Expect up to a 30HP increase on a tuned BMW / Toyota Supra B58 with stock turbo, even more on cars with upgraded turbo.   Features: Compatible with right-hand drive and left-hand drive vehicles Smooth bends for maximum airflow without any drone Up to 30HP increase on the stock turbos, even more on upgraded turbos Lifetime warranty on defects and fitment 90 day return period All orders ship in 1-2 business days Spot on fitment Flex section   Fitment: 2015+ BMW M240i & Xdrive 2016-2019 BMW 340i & Xdrive 2020+2024 BMW M340i & Xdrive * Does not fit 2025 * 2016+ BMW 440i & Xdrive 2016+ BMW 540i & Xdrive 2016+ BMW 740i & Xdrive 2017-2020 X3 M40 2017-2020 X4 M40 2019+ G05 BMW X5 40i & xDrive 2019+ G07 BMW X7 40i & xDrive 2019+ G29 BMW Z4 M40i 2019+ Toyota Supra 3.0L