Compare the2026 Audi S3VS 2026 Mercedes AMG C-Class Sedan

Both the S3 and AMG C-Class Sedan have child safety locks to prevent children from opening the rear doors. The S3 has power child safety locks, allowing the driver to activate and deactivate them from the driver's seat and to know when they're engaged. The AMG C-Class Sedan’s child locks have to be individually engaged at each rear door with a manual switch. The driver can’t know the status of the locks without opening the doors and checking them.

The Audi S3 has standard driver and front passenger side knee airbags mounted low on the dashboard. These airbags help prevent the driver and front passenger from sliding under their seatbelts or the main frontal airbags; this keeps them better positioned during a collision for maximum protection. Knee airbags also help keep the legs from striking the dashboard, preventing knee and leg injuries in the case of a serious frontal collision. The AMG C-Class Sedan doesn’t offer a front passenger side knee airbag.

The S3’s standard lane departure warning system alerts a temporarily inattentive driver when the vehicle begins to leave its lane. A lane departure warning system costs extra on the AMG C-Class Sedan.

Both the S3 and the AMG C-Class Sedan have standard driver and passenger frontal airbags, front and rear side-impact airbags, driver knee airbags, side-impact head airbags, front seatbelt pretensioners, height adjustable front shoulder belts, four-wheel antilock brakes, all wheel drive, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, post-collision automatic braking systems, daytime running lights, blind spot warning systems, rearview cameras, rear cross-path warning and available around view monitors.

The S3’s corrosion warranty is 7 years longer than the AMG C-Class Sedan’s (12 vs. 5 years).

Audi pays for scheduled maintenance on the S3 for 3 years and 30,000 miles. Audi will pay for oil changes, tire rotations, air filter replacements, cabin filter replacement, brake fluid replacement, inspections, and any other required maintenance. Mercedes doesn’t pay scheduled maintenance for the AMG C-Class Sedan.

The Audi S3’s engine uses a cast iron block for durability, while the AMG C-Class Sedan’s engines use an aluminum block. Aluminum engine blocks are much more prone to warp and crack at high temperatures than cast iron.

From surveys of all its subscribers, Consumer Reports’ March 2026 Auto Issue reports that Audi vehicles are more reliable than Mercedes vehicles. Consumer Reports ranks Audi 6 places higher in reliability than Mercedes.

As tested in Motor Trend the Audi S3 is faster than the AMG C 43:

On the EPA test cycle the S3 gets better mileage than the AMG C-Class Sedan running its gasoline engine:

To lower fuel costs and make buying fuel easier, the Audi S3 uses regular unleaded gasoline (premium recommended for maximum performance). The AMG C-Class Sedan requires premium, which can cost on average about 84.9 cents more per gallon.

The S3’s standard tires provide better handling because they have a lower 40 series profile (height to width ratio) that provides a stiffer sidewall than the AMG C-Class Sedan’s standard 45 series tires.

The S3 handles at .95 G’s, while the AMG C 43 pulls only .92 G’s of cornering force in a Car and Driver skidpad test.

For better maneuverability, the S3’s turning circle is 2.8 feet tighter than the AMG C 43’s (36.5 feet vs. 39.3 feet). The S3’s turning circle is 3.2 feet tighter than the AMG C 63 S E’s (36.5 feet vs. 39.7 feet).

The Audi S3 may be more efficient, handle and accelerate better because it weighs about 600 to 1250 pounds less than the Mercedes AMG C-Class Sedan.

The S3 is 11.2 inches shorter than the AMG C-Class Sedan, making the S3 easier to handle, maneuver and park in tight spaces.

The S3 has a 3500 lbs. towing capacity. The AMG C-Class Sedan has no towing capacity.

In poor weather, headlights can lose their effectiveness as grime builds up on their lenses. This can reduce visibility without the driver realizing. The S3 has standard headlight washers to keep headlight output high. The AMG C-Class Sedan doesn’t offer headlight washers.