Mercedes-AMG C63 S W205 M177.1 Modder's Guide

Mercedes-AMG C63/s Overview

Produced from 2015 to 2021, the Mercedes-AMG C63 S (W205) is powered by the legendary hand-built 4.0L twin-turbo M177.1 V8, paired with AMG's 9-speed (facelift) or 7-speed (pre-facelift) MCT transmission and rear-wheel drive. The W205 C63s features strong aftermarket performance potential; with only a tune and basic bolt-on modifications, the M177 can gain well over 150 crank horsepower while maintaining daily drivability.

C63 vs. C63 S and Facelift Differences

W205 C63s Pre-Facelift

W205 C63s Post-Facelift

The C63 base, S, pre-facelift, and post-facelift models are largely the same, but have some  differences that are necessary to understand to extract the most performance possible.  The C63 S model includes a higher factory output (largely due to factory tuning), electronic limited-slip differential, dynamic engine mounts, stiffer suspension, and larger brakes.

The primary difference between the pre and post facelift models (omitting the redesigned styling and tech upgrades) are the upgraded fuel pumps, softer suspension springs, and reworked adaptive suspension tuning. The upgraded fuel pumps enable the post facelift C63/s to run higher ethanol concentrates, resulting in more power when tuned. Typically, pre facelift cars can run up to e20/e25 safely, whereas post facelift cars can run up to e35/e40 safely. However, tuning post-facelift models requires a CPC tune to remove torque limitations.

If you're looking to run higher ethanol blends on a pre facelift car, it is recommended to purchase post-facelift high pressure fuel pumps from a C63s, or W213 E63s HPFP if possible. For blends above e35/e40 on pre or post-facelift models, we recommend Premier Tuning Group's HPFP upgrade.

Performance Modifications (stages)

Note: we recommend pairing any stage ECU tune with a TCU and CPC tune (if facelift) to increase power output, ensure smooth power delivery, and maximize reliability.

Stage 1:

Consists of an ECU, TCU, and CPC tune, cold air intakes, and 91/93 pump fuel. With an aggressive custom tune, expect up to approximately 610 horsepower and 670 lb-ft of torque, reducing 60-130 mph times into the high seven-second range while maintaining factory-like drivability. We recommend changing spark plugs, ignition coils, and performing all other regular maintenance prior to ECU tuning to ensure long-term reliability.

Stage 2:

Adds catless or high-flow downpipes alongside an ECU tune and cold air intakes. This setup typically produces up to 650 horsepower and 760 lb-ft of torque on 93 octane, with 60-130 mph times around the high 6-second range. A TCU and CPC (if post-facelift) tune is highly recommended to optimize shift speed and clutch pressure.

Stage 2+:

Introduces ethanol blends such as E30 together with optimized custom tuning. Depending on fuel quality and calibration, output can reach approximately 700 horsepower and 800 lb-ft of torque while lowering 60-130 times into the low six-second range. Upgraded spark plugs and improved cooling become increasingly important at this level.

Stage 3:

combines hybrid turbochargers with supporting hardware and custom tuning. Running E50 or E85 where supported, well-built setups can approach 850 horsepower and 930 lb-ft of torque with 60-130 mph times around five seconds.

For custom tuning, we recommend working with our experienced Mercedes-AMG specialists at A1 Automotive, MPE California, and Eurocharged. Please reach out to us via email (contact@gappedindustries) or Instagram (@gappedindustries) if you're interested in tuning your Mercedes-AMG,

Exterior Modifications

Front lips significantly improve the vehicle's appearance and can provide a modest increase in front-end stability at higher speeds. Side skirts visually lower the car and complement aggressive wheel fitment, while rear diffusers and rear spoilers (sedan, coupe) complete the rear profile. Mirror caps, steering wheels, and interior carbon are among the easiest upgrades for owners seeking an OEM+ look, and can be easily resold and fitted to other cars.

Wheel upgrades not only transform the appearance of the vehicle but also reduce unsprung weight when selecting forged options. Combined with high-performance tires, they provide one of the most noticeable improvements in both aesthetics and handling.

Carbon fiber hoods and larger exterior aero pieces can reduce some weight and add a more aggressive look, but most exterior modifications should be viewed primarily as cosmetic unless airflow has been tested. Since the C63S is a luxury performance car, subtle OEM+ carbon fiber typically fits the platform best.

Suspension and Handling

While straight-line performance is the primary focus for many owners, lowering springs (sedan, adjust search for coupe) can dramatically improve the W205's stance and aesthetics. Quality coilovers (sedan, adjust search for coupe) can significantly improving both aesthetics and cornering ability if installed and cambered correctly, making them the better (though more expensive) option. A proper alignment following suspension modifications, such as spacers, is essential for maximizing tire life, optimizing camber, and maintaining predictable handling.

Be aware that when lowering your vehicle, tire wear may become uneven and cause tread to deteriorate at an accelerated rate.

Our Recommendations

For owners seeking an OEM+ build, we recommend cold air intakes, subtle carbon fiber exterior components, and a Stage 1 ECU/TCU tune.

For a balanced street build, Stage 2 with catless downpipes, a TCU tune and CPC tune, additional carbon fiber aero, lighter forged wheels, coilovers with spacers, and facelift/E63s fuel pumps (for pre facelift) provides the best combination of reliability and value.

For enthusiasts chasing maximum performance, a Stage 3 or Stage 3+ setup with hybrid turbochargers, upgraded HPFP and LPFP, ethanol tuning, enhanced cooling, and transmission upgrades unlocks the true potential of the M177 platform while maintaining surprising street manners when properly calibrated.

Interested in customizing your Mercedes-AMG or have an inquiry? Contact us via email (contact@gappedindustries) or Instagram (@gappedindustries or @gappedbyamg) for more information.

Frequently Asked Questions (FAQ)

What maintenance should I do before tuning my W205 C63s?

Before tuning your C63 S, make sure the vehicle is up to date on maintenance, including fresh engine oil, properly gapped spark plugs, clean air filters, and healthy ignition coils. It's also recommended to inspect all fluids, check for oil or boost leaks, and scan for any fault codes before installing an ECU tune. Performing preventative maintenance, such as fixing the rear main seal during transmission drop for downpipes install (if using this method), helps maximize reliability and ensure the M177.1 performs at its best.

Is the W205 C63s Reliable?

Yes, the W205 C63s' M177.1 is one of the most reliable modern AMG engines. However, reliability is highly dependent on maintenance frequency. We recommend oil changes roughly every 3-5k miles and regular service 3 times per year, especially when tuned. The engine's biggest pitfall is the rear main seal, which can start leaking as early as 40,000 miles.

How Much Ethanol Can a C63s Run Safely?

We recommend E25 as the limit for the pre-facelift C63s fuel pumps, and E40 as the limit for post-facelift C63s fuel pumps.