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M278 Catless Downpipes – Mercedes E550 W212 (2012–2016) & CLS550 C218 (2012–2018) 4.7L V8 BiTurbo
M278 Catless Downpipes – Mercedes E550 W212 (2012–2016) & CLS550 C218 (2012–2018) 4.7L V8 BiTurbo
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Upgrade your Mercedes M278 BiTurbo V8 with these high-flow catless downpipes. Designed for the 2012–2016 E550 (W212) and 2012–2018 CLS550 (C218), they significantly reduce exhaust restriction for faster turbo spool, improved throttle response, and a deeper, more aggressive exhaust note.
Key Benefits
- High-flow catless design — reduces backpressure at the turbo outlets for quicker boost response and stronger mid-range power
- Direct bolt-on fitment — no cutting or modifications required; replaces the factory catalytic converters
- Deeper exhaust note — more aggressive tone under load with minimal drone during cruising
- Up to +160 hp / +300 lb-ft with ECU calibration.
Vehicle Compatibility
| Years | Model | Chassis | Engine |
|---|---|---|---|
| 2012–2016 | E550 (RWD and 4MATIC) | W212 | M278 4.7L BiTurbo V8 |
| 2012–2018 | CLS550 (RWD and 4MATIC) | C218 | M278 4.7L BiTurbo V8 |
What's Included
Complete left and right downpipe set as pictured. Hardware and gaskets are not included unless shown.
Installation
Direct bolt-on replacement. Average install time 1.5–2.5 hours; professional installation recommended. Re-check for leaks after the initial heat cycles.
Frequently Asked Questions
Will these fit my S550?
No — these downpipes are designed for the 2012–2016 E550 (W212) and 2012–2018 CLS550 (C218) with the M278 BiTurbo V8.
Do I need a tune?
Strongly recommended. Most owners add ECU tuning to avoid check-engine lights and unlock the flow the hardware now allows.
Will I get a check engine light?
Likely, on an untuned car. Removing the cats means the downstream O₂ sensors read differently than the ECU expects. A calibration resolves it properly — we do not recommend defeat devices. Full explanation →
What performance gains can I expect?
Faster turbo spool, sharper throttle response, and stronger mid-range torque on their own. Paired with ECU calibration and supporting modifications, up to +160 hp / +300 lb-ft is achievable. Exact figures depend on your calibration, fuel grade and hardware.
Will they work with aftermarket exhausts?
Yes — designed to work with both factory and aftermarket mid-pipes.
Can I return them?
Yes — 30 days on unused, uninstalled items in their original packaging. Installed or modified exhaust components are not eligible for return, so confirm fitment before you install.
Is there a warranty?
Yes — a 12-month structural warranty, with guaranteed fitment on every model listed above.
Buy With Confidence
- 12-month structural warranty with guaranteed fitment on listed models
- Free U.S. shipping with tracking on every order
- 30-day returns on unused, uninstalled items in original packaging — installed exhaust components are not eligible
- Mercedes specialists — we focus exclusively on Mercedes platforms and know the M278 inside out
- Real support — questions before or after purchase go straight to us, not a call center
Off-road use only. Not legal on emissions-controlled vehicles or public roads.
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