Compare the2022 Audi S4VS 2021 Mercedes AMG A-Class

For enhanced safety, the front seat shoulder belts of the Audi S4 are height-adjustable to accommodate a wide variety of driver and passenger heights. A better fit can prevent injuries and the increased comfort also encourages passengers to buckle up. The Mercedes AMG A-Class doesn’t offer height-adjustable seat belts.

Both the S4 and AMG A-Class have child safety locks to prevent children from opening the rear doors. The S4 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 A-Class’ 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 S4 has a standard Secondary Collision Brake Assist, which automatically applies the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The AMG A-Class doesn’t offer a post collision braking system: in the event of a collision that triggers the airbags, more collisions are possible without the protection of airbags that may have already deployed.

The S4’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 A-Class.

To help make backing out of a parking space safer, the S4’s optional rear cross-path warning system uses sensors in the rear bumper to alert the driver to vehicles approaching from the side, helping the driver avoid collisions. The AMG A-Class doesn’t offer a cross-path warning system.

Both the S4 and the AMG A-Class have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front and rear seatbelt pretensioners, four-wheel antilock brakes, all wheel drive, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, rearview cameras, available blind spot warning systems and around view monitors.

The S4’s corrosion warranty is 7 years longer than the AMG A-Class’ (12 vs. 5 years).

From surveys of all its subscribers, Consumer Reports’ January 2021 Auto Issue reports that Audi vehicles are more reliable than Mercedes vehicles. Consumer Reports ranks Audi 6 places higher in reliability than Mercedes.

The S4’s 3.0 turbo V6 produces 47 more horsepower (349 vs. 302) and 74 lbs.-ft. more torque (369 vs. 295) than the AMG A-Class’ 2.0 turbo 4-cylinder.

To lower fuel costs and make buying fuel easier, the Audi S4 uses regular unleaded gasoline (premium recommended for maximum performance). The AMG A-Class requires premium, which can cost 20 to 55 cents more per gallon.

The S4 has 1.8 gallons more fuel capacity than the AMG A-Class (15.3 vs. 13.5 gallons), for longer range between fill-ups.

An eight-speed automatic is standard on the Audi S4, for better acceleration and lower engine speed on the highway. Only a seven-speed automatic is available for the AMG A-Class.

For better traction, the S4 has larger standard tires than the AMG A-Class (245/40R18 vs. 235/40R18). The S4’s optional tires are larger than the largest tires available on the AMG A-Class (255/35R19 vs. 235/40R18).

The S4 has a standard space-saver spare tire so you can replace a flat tire and drive to have the flat repaired or replaced. A spare tire isn’t available on the AMG A-Class; it requires you to depend on its run-flat tires, which limits mileage and speed before they are repaired. If a run-flat is damaged beyond repair by a road hazard your vehicle will have to be towed. Some tire options on the AMG A-Class don’t have a run-flat feature, either.

For a smoother ride and more stable handling, the S4’s wheelbase is 3.6 inches longer than on the AMG A-Class (111 inches vs. 107.4 inches).

The S4 has .8 inches more front shoulder room, .2 inches more rear headroom, 1.8 inches more rear legroom and .5 inches more rear shoulder room than the AMG A-Class.

The S4 has a much larger trunk than the AMG A-Class (12 vs. 8.6 cubic feet).

With its sedan body style, valet key, locking rear seatbacks and remote trunk release lockout, the S4 offers cargo security. The AMG A-Class’ non-lockable remote release defeats cargo security.

The engine in the S4 is mounted longitudinally (North-South), instead of sideways, as in the AMG A-Class. This makes it easier to service and maintain, because the accessory belts are in front.

Heated windshield washer nozzles are standard on the S4 to prevent washer fluid and nozzles from freezing and help continue to keep the windshield clear in sub-freezing temperatures. The AMG A-Class doesn’t offer heated windshield washer nozzles.

In poor weather, headlights can lose their effectiveness as grime builds up on their lenses. This can reduce visibility without the driver realizing. The S4 Prestige has standard headlight washers to keep headlight output high. The AMG A-Class doesn’t offer headlight washers.

To shield the driver and front passenger’s vision over a larger portion of the windshield and side windows, the S4 has standard extendable sun visors. The AMG A-Class doesn’t offer extendable visors.

Manual rear side window sunshades are available in the S4 to help block heat and glare for the rear passengers. The AMG A-Class doesn’t offer rear side window sunshades.

The S4 has standard heated front seats. Heated front seats cost extra on the AMG A-Class. The S4 Prestige also has standard heated rear seats to keep those passengers extremely comfortable in the winter. Heated rear seats aren’t available in the AMG A-Class.

The Audi A4/S4 outsold the Mercedes A-Class by 77% during the 2021 model year.