If you drive a BMW M5 or X5M powered by the ferocious S63 twin-turbo V8, chances are you’ve already tasted the raw power this engine delivers. But what if we told you there’s a way to unleash even more performance, responsiveness, and sound from your already high-performing machine? Enter s63 downpipes—a must-have mod for any enthusiast serious about getting the most from their Bavarian beast.

Whether you’re chasing dyno numbers, track performance, or a throatier exhaust note, upgrading your S63 downpipes is one of the smartest first steps you can take. In this guide, we break down everything you need to know about s63 downpipes, from performance gains to emissions considerations and buying tips.

What Are Downpipes and Why Upgrade?

Understanding Downpipes on the S63 Engine

Downpipes are the exhaust components that connect your turbochargers to the midpipe. On the S63, which features dual twin-scroll turbos, the factory downpipes are equipped with restrictive catalytic converters. These help with emissions, but they also create backpressure that limits your engine’s true potential.

How S63 Downpipes Make a Difference

Upgrading to high-flow or catless s63 downpipes reduces exhaust restriction, allowing turbochargers to spool faster and generate more boost. The result? More power, quicker throttle response, and a deeper, more aggressive exhaust tone. It’s not uncommon to see gains of 40–60 hp and significant torque increases, especially when paired with a proper tune.

Catted vs. Catless S63 Downpipes

Catted S63 Downpipes

Catted s63 downpipes feature high-flow catalytic converters. These maintain some level of emissions compliance and reduce the chance of triggering a CEL (check engine light). They’re a great choice for drivers who want better performance and sound without fully removing emissions components.

Pros:

• Emissions friendlier

• Less exhaust odor

• May pass visual inspection

Cons:

• Less power gain than catless

• More expensive

Catless S63 Downpipes

Catless s63 downpipes remove the catalytic converters entirely, maximizing flow. These deliver the biggest performance gains and the most aggressive sound. However, they are intended for off-road or racing use only due to emissions non-compliance.

Pros:

• Maximum horsepower and torque

• Loud, raw exhaust tone

• Lower cost

Cons:

• Strong exhaust fumes

• Guaranteed CEL unless tuned

• Not emissions legal

Performance Gains You Can Expect

Dyno-Proven Results with S63 Downpipes

When paired with a Stage 2 tune, high-quality s63 downpipes can add:

• +50–70 hp at the wheels

• +70–100 lb-ft of torque

• Faster spool and midrange punch

• Sharper throttle response

On vehicles like the F90 M5 or F95 X5M, these gains are immediately noticeable, especially when launching or in roll races.

Improved Turbo Efficiency

The S63’s twin turbos benefit massively from reduced backpressure. With upgraded s63 downpipes, turbos can spool quicker and stay in their sweet spot longer—ideal for both spirited street driving and competitive performance.

What to Look for When Buying S63 Downpipes

Material and Build Quality

Stick to s63 downpipes made from 304 stainless steel or better. This ensures durability under high temperatures and long-term reliability. Look for precision welds, CNC flanges, and a smooth internal finish to avoid turbulence.

Fitment and Compatibility

Fitment is crucial. Ensure the s63 downpipes are specifically designed for your S63 variant—whether it’s in the F90 M5, F95 X5M, F10 M5, or F85 X5M. Some downpipes are model-specific, especially regarding sensor placement and turbo flanges.

Brand Reputation

Top brands known for high-quality s63 downpipes include:

• VRSF

• ARM Motorsports

• Active Autowerke

• Evolution Racewerks

• BMS

Always check reviews, dyno results, and whether the manufacturer offers fitment guarantees.

Installation and Tuning

Professional Installation Recommended

Installing s63 downpipes is not a beginner DIY job. The twin-turbo layout is tight, and removal of stock downpipes requires patience and expertise. A professional installation will ensure proper fitment, avoid exhaust leaks, and protect your O2 sensors.

Don’t Forget the Tune

To get the most from your s63 downpipes, you’ll need a tune—especially if you go catless. A Stage 2 ECU tune will:

• Optimize fueling and ignition

• Eliminate CEL codes

• Unlock full performance gains

Some tunes even allow for burble adjustments, valve control, and ethanol compatibility.

Sound Transformation with S63 Downpipes

Beyond power, one of the most noticeable upgrades is sound. With catted s63 downpipes, you’ll get a throatier, more exotic note without drone. Catless setups go even further, turning your M5 or X5M into a snarling, fire-breathing monster. Cold starts become aggressive, and WOT pulls unleash turbo whooshes and deep roars that no stock setup can match.

Legal and Emissions Considerations

Keep in mind, s63 downpipes—especially catless—are not legal for street use in many areas. Always check your local emissions laws. For dual-use setups, consider:

• Swappable midpipes or valves

• High-flow catted options

• Stealthy exhaust tips to maintain stock appearance

Responsible modification is key to enjoying the performance without attracting unwanted attention.

Final Thoughts – Maximize Your S63’s Potential

If you’re serious about maximizing the power, sound, and overall driving thrill of your BMW M5 or X5M, upgrading to s63 downpipes should be at the top of your mod list. From insane torque gains to a spine-tingling exhaust note, the difference is dramatic and immediate.

Choose high-quality s63 downpipes, pair them with a proper tune, and have them installed professionally. Whether you’re carving canyons, dominating track days, or just enjoying your morning commute with a grin, the right downpipes will completely transform your S63-powered beast.