Upgrading the exhaust system on a Mercedes-AMG C63 S Sedan is one of the most rewarding modifications you can make. The factory exhaust already delivers a commanding V8 growl, but a performance exhaust system from Mercedes-AMG or a reputable aftermarket brand unlocks sharper throttle response, weight savings, and a more aggressive soundtrack. While the process is straightforward for an experienced DIY enthusiast, it demands careful attention to detail, the right tools, and a clean workspace. This expanded guide covers every step from preparation through final testing, with professional tips to ensure a leak-free, secure installation that preserves the car's factory fit and finish.

Tools and Materials Needed

Before lifting the car, gather all the required components and tools to avoid mid-job interruptions. A complete performance exhaust system for the C63 S typically includes downpipes, center section with resonators or X-pipe, rear muffler assembly, clamps, hangers, and gaskets. Verify the kit is designed for the 2015–2021 C63 S (W205) to guarantee correct fitment.

  • Exhaust system kit (Mercedes-AMG Performance Exhaust or equivalent)
  • Socket and wrench set – Metric sizes: 10, 13, 15, 18 mm. A flex-head ratchet helps reach tight spots.
  • Torque wrench (range 20–80 Nm) for final bolt tightening to spec.
  • Pry bar or exhaust hanger removal tool – A dedicated tool prevents damage to rubber hangers.
  • Jack and jack stands (minimum 2-ton capacity) – Never rely on a hydraulic jack alone.
  • Penetrating oil (e.g., WD-40 Specialist or PB Blaster) for rusted fasteners.
  • Safety goggles and mechanic’s gloves.
  • Shop towels and a drop cloth – Exhaust soot and old gasket debris are messy.
  • Optional: 4-post lift – If using a lift, ensure adapters clear the exhaust path.

Pre-Installation Preparation

Preparation sets the stage for a smooth installation. Follow these steps exactly to avoid electrical issues and ensure safe vehicle support.

  • Park on a level surface and engage the parking brake. Chock the rear wheels for extra safety.
  • Disconnect the battery – The C63 S uses an intelligent alternator and battery management system; disconnecting avoids voltage spikes. Use a 10 mm socket to loosen the negative terminal clamp and tuck the cable away.
  • Raise the vehicle – Position the jack under the designated front lift point (refer to owner’s manual). Raise until jack stands can be placed at the two rear lift points and one front center point (or use four stands). Set the stands at equal heights and shake the car to confirm stability.
  • Allow the exhaust to cool completely – If the car was driven, wait at least one hour. Hot exhaust components cause severe burns.

Removing the Stock Exhaust System

Factory exhaust removal is reversed for installation of the new system. Work methodically, labeling hardware if reusing parts.

  • Spray penetrating oil on all exhaust flange bolts and hanger rubber mounts. Let it soak for 10 minutes.
  • Unbolt the rear muffler (if separate) – Typically four 13 mm bolts secure it to the hanger brackets. Support the muffler with a second jack or have a helper hold it.
  • Disconnect the exhaust from the catalytic converters – Two 15 mm bolts at each bank. The bolts may be corroded; use a breaker bar if needed. Do not force – apply more penetrating oil and wait.
  • Detach the center section – Remove the clamp bolts at the connection points. Slide the pipes apart, noting the orientation of any spring-loaded flanges.
  • Remove the hanger rings – Use a pry bar or exhaust hanger tool to pull the rubber mounts off the metal hangers. A little soapy water helps them slide.
  • Lower each section – With all fasteners free, carefully lower the stock exhaust. The rear section is heavy; use a helper to avoid dropping it on the floor or damaging the car.

Common pitfalls: Stripped bolts are a risk on higher-mileage cars. If a bolt spins without coming out, use heat (if safe around fuel lines) or a bolt extractor. If you absolutely cannot remove a flange bolt, cut it with a reciprocating saw and replace it with a new OEM bolt – available at any Mercedes dealer or online parts store.

Inspecting the Factory Exhaust Mounts

While the old system is off, inspect the rubber hangers. If they are cracked or floppy, replace them with new ones. Mercedes sells a genuine hanger kit (part number A205 490 00 15) that ensures the new exhaust sits correctly and reduces vibration transfer.

Installing the Performance Exhaust System

Lay out the new exhaust components in order from front to back. Compare the kit against the car’s layout to confirm you have all pieces.

  • Install new gaskets at the catalytic converter flanges. Most performance kits include copper or composite gaskets; if not, purchase OEM gaskets (two needed).
  • Attach the downpipes – If your kit includes downpipes (some sold separately), bolt them to the turbos first, then connect to the catalytic converter or straight pipe. Torque to 45 Nm.
  • Position the center section – Slide the pipe into the downstream connection. Use new clamps; do not reuse old ones. Finger-tighten first.
  • Mount the rear muffler – Hang it on the rubber hangers. The C63 S has four hanger points. Push the rubber rings fully onto the metal tabs; a small amount of silicone spray helps.
  • Align all pipes – Ensure even clearance around the rear differential, subframe, and underbody panels. Rotate pipes to avoid contact. The exhaust tips should sit centered in the bumper cutouts.
  • Tighten all clamps and bolts – Start from the front and work rearward. Use a torque wrench: flange bolts 45–50 Nm, band clamps 20–25 Nm. Re-tighten after a short test drive as everything settles.

Adjusting Exhaust Tips for Perfect Fitment

Adjust the tips before finalizing all clamps. Loosen the tip-to-muffler clamp, set the tip flush with the bumper surround, and tighten to 15 Nm. The tips should not touch the bumper or vibrate against it.

Finalizing the Installation

With the new exhaust fully assembled and tightened, complete these final steps.

  • Reconnect the battery – Tighten the negative terminal to 10–12 Nm. Do not overtighten.
  • Lower the vehicle – Remove jack stands one at a time, then lower the jack. Allow the suspension to settle.
  • Perform a visual inspection – Check all clamps, hangers, and clearance. Look for any loose objects left under the car.
  • Start the engine – Listen for immediate rattles or scraping. Let it idle for two minutes to warm the exhaust and expand connections.

Testing and Leak Checking

Leaks rob power and create irritating noise. Testing identifies issues early.

  • Listen for hissing or chuffing – Use a mechanics stethoscope or a rubber hose near each joint. A leak will sound like a rapid pulse.
  • Feel for exhaust gas – Carefully pass your hand (protected with a glove) near flanges while the engine runs. Do not touch hot pipes.
  • Use a smoke machine – If you have access, introduce smoke into the tailpipe and look for wisps around joints. This is the most reliable method.
  • Check for OBD trouble codes – A performance exhaust without proper oxygen sensor management may trigger a check engine light. If the kit includes oxygen sensor spacers or tuning, ensure they are installed correctly. Drive the car for 10 minutes and scan for codes.
  • Test drive – Take the car on a quiet road. Accelerate gently and then full throttle. Listen for drone at cruising speeds (2,000–2,500 rpm) and any vibrations. If drone is excessive, check that the exhaust is not contacting the underbody. Some systems require heat shield adjustments.

Maintenance and Longevity Tips

A performance exhaust system requires occasional care to stay looking and sounding its best.

  • Clean the tips regularly – Use a dedicated metal polish (e.g., Mother’s Mag & Aluminum Polish) and a microfiber cloth. Avoid abrasive pads that scratch chrome or titanium finishes.
  • Inspect hangers every oil change – Rubber hardens over time. Replace at the first sign of cracking or sagging.
  • Check clamp torque after 500 miles – Heat cycles can loosen connections. Re-torque all clamps to spec.
  • Protect against corrosion – If you live in a salt-belt region, consider an annual undercoating inspection. Stainless steel resists rust, but fasteners can still corrode.
  • Listen for changes – A sudden increase in volume or a new rattle indicates a loose part or failed hanger. Address it promptly to avoid damage.

Frequently Asked Questions

Will a performance exhaust void my factory warranty?

An aftermarket exhaust alone does not automatically void the entire warranty, but any damage caused directly by the modification may not be covered. Mercedes-AMG Performance Parts carry their own warranty when installed by a certified dealer. For non-Mercedes kits, keep your stock exhaust and reinstall it before dealer visits if you are concerned. For more details, see Mercedes-AMG Performance Parts.

How much louder will the car be?

Expect a noticeable increase in sound, especially under full throttle. Most performance systems for the C63 S feature a valved muffler (similar to the factory AMG Dynamic Exhaust) that allows quiet cruising by bypassing the muffler flaps. Without valves, the car will be significantly louder at all times. Check local noise ordinances.

Do I need a tune after installation?

If you only change the cat-back portion (from the catalytic converters rearward), no tune is required. If you replace the downpipes or remove catalysts, an ECU tune is strongly recommended to prevent check engine lights and optimize performance. Many tuning companies offer off-the-shelf calibrations for the M177 engine. Consult a reputable tuner like Eurocharged or Weistec Engineering.

Can I install the system myself?

Yes, provided you have basic mechanical skills, the right tools, and a safe workspace. This guide covers the process. If you are uncomfortable working under a heavy car, or if your exhaust system includes welding (for custom connections), have it installed by a professional shop.

Conclusion

Installing a performance exhaust system on your Mercedes-AMG C63 S Sedan transforms the driving experience with deeper, more responsive sound and subtle power gains. While the process requires careful attention to torque specs, hanger alignment, and leak testing, the satisfaction of doing it yourself—and the daily pleasure of hearing your V8 sing—is worth the effort. Keep your stock exhaust for future resale, maintain the new system regularly, and enjoy every mile behind that famous AMG steering wheel.