How to Tell if a Mercedes-AMG C63S Has the AMG Performance Exhaust
Decoding factory options on a used Mercedes-AMG C63 or C63S can be confusing when cosmetic packages mimic hardware upgrades.
The Short Answer (TL;DR)
To verify if a W205 Mercedes-AMG C63S has the AMG Performance Exhaust (Option Code U78), look for the dedicated exhaust dual-tailpipe button on the center console. Tip color is strictly cosmetic: black tips indicate the Night Package, not the performance exhaust. You can also look into the exhaust tips for dual inner pipes per side or decode the factory VIN.
The Community Question
Prospective buyers and new owners frequently mistake cosmetic styling packages for mechanical equipment on the W205 Mercedes-AMG C63 and C63S. A common misconception is that black chrome exhaust tips signify the factory AMG Performance Exhaust (PE), while silver tips mean the standard exhaust. Additionally, drivers notice massive acoustic differences between two seemingly identical cars, leading to confusion about what hardware is installed.
The Mechanical Diagnosis: Why This Happens
Mercedes-Benz separated visual trim packages from powertrain and exhaust options on the W205 platform:
- Exhaust Tip Color: Black tips are part of the optional AMG Night Styling Package (Option Code P60/P55). Silver/chrome tips are standard equipment. Neither indicates the underlying exhaust hardware.
- Center Console Controls: Vehicles equipped with the switchable AMG Performance Exhaust (Option Code U78) feature a dedicated button on the lower center console showing an icon of dual exhaust pipes with an LED indicator. Standard non-PE cars lack this switch completely and only adjust exhaust tone indirectly through Dynamic Select drive modes.
- Physical Pipe Configuration: Inspecting the inside of the rear diffuser reveals distinct piping. The AMG Performance Exhaust routes two pipes per side into the decorative outer tips (one round, one squarish bypass route operated by active electronic valves). The standard exhaust uses a single pipe entering the rear shroud.
- Sound Discrepancies Between Cars: Even when two cars have the U78 Performance Exhaust, differences in acoustic volume and exhaust overrun (pops and bangs) occur. Mercedes-Benz rolled out multiple ECU and CPC software updates between 2015 and 2020 that altered valve mapping and decel fuel cut tables. Furthermore, aftermarket exhaust valve modules (like ASR or RennTECH EVMs) or secondary catalytic converter deletes radically change volume.
The Engineering Solution: Maximizing AMG Exhaust Flow and Sound
If you purchase a non-PE W205 C63 or find the factory valve logic too restrictive, the factory valving typically only opens fully at higher RPMs or specific load thresholds, even in Sport+ mode. Installing an aftermarket electronic valve controller overrides factory ECU limits, forcing the bypass valves 100% open on command. For standard exhaust cars, retrofitting an aftermarket valved cat-back exhaust or high-flow downpipes yields significant exhaust gas velocity gains and the authentic BiTurbo V8 rumble without factory software restrictions.
Recommended Solution: Upgrade to an Active Exhaust Valve Controller Module or a high-flow cat-back exhaust system paired with an ECU calibration to optimize exhaust gas scavenging, reduce turbo backpressure, and deliver consistent acoustics across all drive modes.
Frequently Asked Questions
Can I retrofit the OEM AMG Performance Exhaust to a standard C63?
While physically possible, retrofitting the OEM U78 system requires replacing the entire exhaust tract, installing wiring harnesses, vacuum actuators or electronic valve motors, replacing the center console switch bank, and coding the SAM and ECU modules. An aftermarket valved exhaust system is far more cost-effective and simpler to install.
Why is my 2019+ facelift C63 quieter than an early 2015-2018 model?
Facelift (2019-2021) W205 C63 models received updated engine management software and particulate filters (OPF/GPF in European and select global markets) to meet stricter emissions and noise regulations, significantly reducing exhaust crackles and overall decibels compared to pre-facelift models.
