The latest generation of BMW M power is here, and the S68 twin-turbo V8 engine is at its core—found in the G90 M5, XM, and other flagship M models. While the S68 delivers impressive performance straight from the factory, there’s a simple yet powerful upgrade that can take it to the next level: a BMW S68 downpipe.

Whether you’re chasing horsepower, better throttle response, or a more aggressive exhaust note, this guide will walk you through everything you need to know about upgrading your BMW S68 downpipe.

What Is a BMW S68 Downpipe?
A downpipe is a crucial part of a turbocharged exhaust system. It connects the turbochargers to the mid-pipes or the rest of the exhaust. The stock downpipe is equipped with restrictive catalytic converters to meet emissions standards, but these also restrict performance.

A performance BMW S68 downpipe—especially a high-flow or catless version—reduces backpressure, increases exhaust gas flow, and unleashes the full potential of your twin-turbo V8.

Key Benefits of Upgrading to a BMW S68 Downpipe
1. Increased Horsepower and Torque
Swapping in a performance BMW S68 downpipe allows your turbos to spool more efficiently. When paired with a proper ECU tune, you can see gains of 20–40+ horsepower and significant torque increases.

2. Sharper Turbo Response
Improved flow means less turbo lag. You’ll feel quicker throttle response, more immediate boost delivery, and overall sharper driving dynamics.

3. Aggressive Exhaust Sound
One of the most noticeable upgrades is the sound. A performance BMW S68 downpipe brings out a deeper, more raw and aggressive tone from the V8—especially under hard acceleration.

4. Foundation for Future Mods
If you plan on tuning your car further—like upgrading turbos, intercoolers, or switching to full exhaust systems—a downpipe is a must-have supporting mod.

Recommended Product: AXI Performance BMW S68 Downpipe
If you’re looking for a high-quality, precision-engineered option, AXI Performance offers one of the best BMW S68 downpipe solutions on the market. Built with high-grade stainless steel, TIG welding, and designed for maximum flow, it’s perfect for both street and track applications.

Key features:

Mandrel-bent tubing for unrestricted flow

OEM-like fitment

Available in catted and catless versions

Designed specifically for the BMW S68 engine platform

Installation & Tuning Notes
While the installation of a BMW S68 downpipe can be done by experienced enthusiasts, professional installation is recommended for best results. To avoid check engine lights (CEL), it’s important to pair the upgrade with a proper ECU tune that disables the post-cat O2 sensor monitoring and optimizes the engine for the new flow characteristics.

If you’re serious about unlocking the true potential of your BMW’s S68 engine, upgrading the downpipe is one of the smartest and most effective mods you can make. From added power and responsiveness to a throatier exhaust note, the benefits are immediate and impactful.

Upgrade your BMW today with the AXI Performance BMW S68 downpipe and experience the transformation every M enthusiast craves.