The C-Class Sedan has a standard front seat center airbag, which deploys between the driver and front passenger, protecting them from injuries caused by striking each other in serious side impacts. The A6 doesn't offer front seat center airbags.

Over 200 people are killed each year when backed over by motor vehicles. The C-Class Sedan offers an optional Maneuvering Brake Function that uses rear sensors to monitor for objects to the rear and automatically applies the brakes to prevent a collision. The A6 doesn't offer automatic braking for stationary objects directly to the rear.

Both the C-Class Sedan and the A6 have standard driver and passenger frontal airbags, front side-impact airbags, driver knee airbags, side-impact head airbags, front seatbelt pretensioners, height adjustable front shoulder belts, four-wheel antilock brakes, 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, driver alert monitors, available all wheel drive, lane departure warning systems and around view monitors.

The Mercedes C-Class Sedan has achieved the Insurance Institute for Highway Safety's (IIHS) highest rating of “Top Safety Pick Plus” for the 2025 model year. This distinction is based on its exceptional performance in IIHS' rigorous battery of safety tests. Specifically, it earned a “Good” rating in the latest, more stringent moderate overlap front crash test, a “Good” result in the updated side impact test, and an “Acceptable” to “Good” score in the revised pedestrian crash prevention test. The A6 has not yet been evaluated by the IIHS for 2025.

There are over 25 percent more Mercedes dealers than there are Audi dealers, which makes it easier should you ever need service under the C-Class Sedan's warranty.

J.D. Power and Associates' 2025 Initial Quality Study of new car owners surveyed provide the statistics that show that Mercedes vehicles are better in initial quality than Audi vehicles. With 59 fewer problems per 100 vehicles, JD Power ranks Mercedes higher than Audi.

J.D. Power and Associates' 2025 survey of the owners of three-year-old vehicles provides the long-term dependability statistics that show that Mercedes vehicles are more reliable than Audi With 30 fewer problems per 100 vehicles in the first three years of ownership, J.D. Power ranks Mercedes higher than Audi.

On the EPA test cycle the C-Class Sedan gets better mileage than the A6:

Regenerative brakes improve the C-Class Sedan's fuel efficiency by converting inertia back into energy instead of wasting it. The A6 doesn't offer a regenerative braking system.

The C-Class Sedan has 1.3 gallons more fuel capacity than the A6 (17.4 vs. 16.1 gallons), for longer range between fill-ups.

In its Green Vehicle Guide, the U.S. Environmental Protection Agency (EPA) rates the Mercedes C-Class Sedan higher (7 out of 10) than the Audi A6 (4). This means the C-Class Sedan produces up to 13.2 pounds less smog-producing pollutants than the A6 every 15,000 miles.

A nine-speed automatic is standard on the Mercedes C-Class Sedan, for better acceleration and lower engine speed on the highway. Only a seven-speed automatic is available for the A6.

The C-Class Sedan's standard 245/40R18 rear tires provide better handling because they have a lower 40 series profile (height to width ratio) that provides a stiffer sidewall than the A6's standard 45 series tires.

The C-Class Sedan's drift compensation steering can automatically compensate for road conditions which would cause the vehicle to drift from side to side, helping the driver to keep the vehicle straight more easily. The A6 doesn't offer drift compensation steering.

For better maneuverability, the C-Class Sedan's turning circle is 2.8 feet tighter than the A6's (37.6 feet vs. 40.4 feet).

The Mercedes C-Class Sedan may be more efficient, handle and accelerate better because it weighs about 350 to 500 pounds less than the Audi A6.

The C-Class Sedan is 9.8 inches shorter than the A6, making the C-Class Sedan easier to handle, maneuver and park in tight spaces.

The design of the Mercedes C-Class Sedan amounts to more than styling. The C-Class Sedan has an aerodynamic coefficient of drag of .24 Cd. That is significantly lower than the A6 (.31) and many sports cars. A more efficient exterior helps keep the interior quieter and helps the C-Class Sedan get better fuel mileage.

The C-Class Sedan has .4 inches more front legroom and .2 inches more rear shoulder room than the A6.

Pressing a switch automatically lowers the C-Class Sedan's rear seats, to make changing between passengers and cargo easier. The A6 doesn't offer automatic folding seats.

Heated windshield washer nozzles are optional on the C-Class Sedan to prevent washer fluid and nozzles from freezing and help continue to keep the windshield clear in sub-freezing temperatures. The A6 doesn't offer heated windshield washer nozzles.

The C-Class Sedan has a 115-volt a/c outlet on the center console, allowing you to recharge a laptop or run small household appliances without special adapters that can break or get misplaced. The A6 doesn't offer a house-current electrical outlet.

The C-Class Sedan is available in both rear-wheel drive and all-wheel drive configurations. The A6 doesn't offer a two-wheel drive configuration.

The Mercedes C-Class outsold the Audi A6/S6/RS 6 by over four to one during 2024.