Verified
Spools like a different car
Backpressure gone. Boost comes in a full 400rpm sooner and it pulls all the way to redline now. Fitment was dead-on — no massaging, no fighting the O2 bungs.
Marcus D.
GL550 M278 Biturbo Downpipes
$999.00
Sale price
$999.00
Regular price
$1,350.00
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X166 · M278
GL550 M278 Biturbo Downpipes
Much like our approach to other M278-powered Mercedes SUVs, we recognized that the versatile GL550 could massively benefit from unrestricted exhaust flow. Whether you are towing a heavy load or chasing more power, MBH Motorsports GL550 Downpipes are engineered to...
- Engine Mercedes-Benz M278 4.7L V8 Biturbo
- Chassis Mercedes-Benz GL550 (X166)
$999.00
Sale price
$999.00
Regular price
$1,350.00
- Made in the USAPhoenix, Arizona
- Hand TIG-weldedMiller Dynasty
- Lifetime warrantyUncoated headers & downpipes
On the dyno
What it puts down.
The gains listed for this part, measured at the wheels. Your numbers will move with the car, fuel and tune.
- Listed gain
- Listed with a “+”: this much or more
Listed gains · at the wheels
Horsepower gain · with ECU tune
80 or more wheel horsepower gain
From this part’s specs: 80+ whpShows the listed range, not a dyno sheet.
Inside the build
What sets these downpipes apart
Fitment
Built for these cars
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X166X166M278
Your car on the list? You're good to go.
The details
Specs & details
Much like our approach to other M278-powered Mercedes SUVs, we recognized that the versatile GL550 could massively benefit from unrestricted exhaust flow. Whether you are towing a heavy load or chasing more power, MBH Motorsports GL550 Downpipes are engineered to eliminate severe factory exhaust restrictions by upgrading the piping diameter to a high-flowing 3 inches.
When mated with proper performance ECU tuning, these downpipes allow the biturbo V8 to breathe freely and unlock monster power. This system completely transforms your GL550 into a heavy-hitting luxury SUV capable of leaving dedicated sports cars and rival performance vehicles in the dust.
Easy Installation & Bolt-On Design
Beyond the exceptional performance and premium USA craftsmanship, we engineered this system for maximum convenience in the garage. Installation is incredibly straightforward; designed as a direct bolt-on upgrade, this downpipe system can easily be installed in about an hour using basic hand tools with zero custom fabrication or cutting required.
Key Features:
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Monster Power Gains: 80+ hp with tuning. Alleviates extreme factory backpressure to unlock massive horsepower and torque when paired with an ECU tune.
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High-Flow 3-Inch Tubing: Upgrades restrictive factory piping to smooth, 3-inch diameter tubing for maximum exhaust velocity.
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Enhanced Utility & Performance: Improves low-end torque for heavy towing while delivering aggressive top-end power.
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1-Hour Bolt-On Installation: Precision-engineered for a seamless, direct bolt-on fitment that installs easily with simple hand tools.
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USA Craftsmanship: Proudly hand-fabricated in the USA for lifetime durability and extreme thermal resistance.
Compatibility:
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Engine: Mercedes-Benz M278 4.7L V8 Biturbo
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Chassis: Mercedes-Benz GL550 (X166)
Disclaimer: For off-road racing and competition use only. This product is not intended to be installed on a registered vehicle for use on public roads or highways and may never be installed on a registered or licensed vehicle for use on any public roads and highways.
$999.00
Questions about this part?Email us your question or VIN.
Email us
Email us
Straight from the owners
Built, bolted, proven
Real cars. Real dyno sheets. Here's what owners say after the headers go on.
5.0 / 5
3 verified builds
Ready for yours?
Complete your X166 build
Before you order
Straight answers
The questions we get asked most.
Still not sure?
Email us your question or VIN and we'll confirm fitment before you order.
sales@mbhmotorsports.com
Will this fit my car?
It's built for X166 · M278. Pick your car in the fitment check at the top of this page to confirm. Not listed, or engine swapped? Email us your VIN and we'll confirm fitment before you order.
Is there a warranty?
Yes. Headers and downpipes we build carry a lifetime warranty (coated or painted finishes excluded). Email us with any warranty question.
Where is it made?
Right here in the USA, in our Phoenix, Arizona shop.
Can I ask a question before I order?
Yes. Email us with your car and your question and we'll get back to you. If you're unsure about fitment, include your VIN.