Exhaust› Exhaust Pipes, Systems and Components

MAD

B58 4.5-Inch Catted Downpipe

$650.00

SKU: MAD-3056

In Stock
In Stock
Ships by Sep 12
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The MAD B58 4.5" Catted Downpipe is an exhaust performance upgrade designed to improve airflow and sound on select BMW and Toyota Supra models. Constructed from 304 stainless steel, it features high-flow catalytic converters and a flex section to handle extreme temperatures while reducing back pressure.

This bolt-on component installs directly to the stock exhaust system without requiring cutting or welding. It is compatible with both left-hand and right-hand drive configurations and is intended for race use only.
Show original supplier description
The MAD B58 4.5" Catted Downpipe is an engineered exhaust solution for B58-powered BMW F and G chassis vehicles and the Toyota Supra. By replacing the restrictive stock downpipe, this unit optimizes exhaust gas velocity, resulting in increased horsepower, improved torque, and sharper throttle response. Its design includes 200 CEL high-flow catalytic converters that balance emission reduction with performance, paired with a dedicated flex section to endure high-heat conditions. Manufactured from premium 304 stainless steel, the downpipe features smooth mandrel bends to maximize flow and eliminate drone. Fitment covers a range of B58 applications, including the 2015+ BMW M240i & Xdrive, 2016-2019 BMW 340i & Xdrive, 2020+ BMW M340i & Xdrive, 2016+ BMW 440i & Xdrive, 2016+ BMW 540i & Xdrive, 2016+ BMW 740i & Xdrive, 2017-2020 X3 M40, 2017-2020 X4 M40, and 2019+ Toyota Supra 3.0L. Please note this product is for race use only.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

BrandMAD
Part NumberMAD-3056
CategoryExhaust

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Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

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