Compare the2026 Kia K4VS 2026 Audi S3

For enhanced safety, the front and rear seat shoulder belts of the Kia K4 have pretensioners to tighten the seatbelts and eliminate dangerous slack in the event of a collision and force limiters to limit the pressure the belts will exert on the passengers. The Audi S3 doesn’t offer pretensioners for its rear seat belts.

In the past twenty years hundreds of infants and young children have died after being left in vehicles, usually by accident. When turning the vehicle off, drivers of the K4 are reminded to check the back seat if they opened the rear door before starting out. The S3 doesn’t offer a back seat reminder.

With its standard Forward Collision-Avoidance Assist, the Kia K4 is better at preventing collisions with pedestrians than the Audi S3, according to the Insurance Institute for Highway Safety:

In a Vehicle-to-Vehicle Frontal Crash Prevention 2.0 test conducted by the Insurance Institute for Highway Safety (IIHS), the Kia K4 achieved a “Acceptable” rating - the second highest possible - for its performance in forward collision warning and automatic braking systems, demonstrating its excellent capabilities in preventing collisions. The Audi S3 has not been tested.

Over 200 people are killed each year when backed over by motor vehicles. The K4 GT-Line Turbo offers optional Reverse Parking Collision-Avoidance Assist that uses rear sensors to monitor for objects to the rear and automatically applies the brakes to prevent a collision. The S3 doesn’t offer automatic braking for stationary objects directly to the rear.

The K4’s driver alert monitor detects an inattentive driver then sounds a warning and suggests a break. According to the NHTSA, drivers who fall asleep cause about 100,000 crashes and 1500 deaths a year. The S3 doesn’t offer a driver alert monitor.

Both the K4 and the S3 have standard driver and passenger frontal airbags, front and rear side-impact airbags, side-impact head airbags, height adjustable front shoulder belts, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, lane departure warning systems, rearview cameras, available blind spot warning systems, around view monitors and rear cross-path warning.

The Kia K4 Sedan (Built after January 2025) 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 a “Good” score in the revised pedestrian crash prevention test. The S3 is not even a standard “Top Safety Pick” for 2025.

The K4 comes with a full 5-year/60,000-mile basic warranty, which covers the entire car and includes 24-hour roadside assistance. The S3’s 4-year/50,000-mile basic warranty expires 1 year or 10,000 miles sooner.

Kia’s powertrain warranty covers the K4 6 years and 50,000 miles longer than Audi covers the S3. Any repair needed on the engine, transmission, axles, joints or driveshafts is fully covered for 10 years or 100,000 miles. Coverage on the S3 ends after only 4 years or 50,000 miles.

There are almost 3 times as many Kia dealers as there are Audi dealers, which makes it much easier should you ever need service under the K4’s warranty.

J.D. Power and Associates rated the K4 second among small cars in their 2025 Initial Quality Study. The S3 isn’t in the top three in its category.

J.D. Power and Associates’ 2025 Initial Quality Study of new car owners surveyed provide the statistics that show that Kia vehicles are better in initial quality than Audi vehicles. J.D. Power ranks Kia above average in initial quality. With 88 more problems per 100 vehicles, Audi is rated below average.

J.D. Power and Associates’ 2025 survey of the owners of three-year-old vehicles provides the long-term dependability statistics that show that Kia vehicles are more reliable than Audi vehicles. J.D. Power ranks Kia above average in long-term dependability. With 6 more problems per 100 vehicles in the first three years of ownership, Audi is rated below average.

On the EPA test cycle the K4 Sedan gets better mileage than the S3:

On the EPA test cycle the K4 Hatchback gets better mileage than the S3:

To lower fuel costs and make buying fuel easier, the Kia K4 uses regular unleaded gasoline. The S3 requires premium for maximum efficiency, which can cost on average about 84.9 cents more per gallon.

In its Green Vehicle Guide, the U.S. Environmental Protection Agency (EPA) rates the Kia K4 higher (6 out of 10) than the Audi S3 (4). This means the K4 produces up to 12.1 pounds less smog-producing pollutants than the S3 every 15,000 miles.

An eight-speed automatic is standard on the Kia K4 GT-Line Turbo, for better acceleration and lower engine speed on the highway. Only a seven-speed automatic is available for the S3.

The K4 has a standard continuously variable transmission (CVT). With no “steps” between gears, it can keep the engine at the most efficient speed for fuel economy, or keep it at its peak horsepower indefinitely for maximum acceleration. The S3 doesn’t offer a CVT.

The K4 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 S3; 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 S3 don’t have a run-flat feature, either.

For a smoother ride and more stable handling, the K4’s wheelbase is 3.5 inches longer than on the S3 (107.1 inches vs. 103.6 inches).

For better handling and stability, the average track (width between the wheels) on the K4 is 1.3 inches wider in the front and 2.7 inches wider in the rear than the track on the S3.

For better maneuverability, the K4’s turning circle is 1.3 feet tighter than the S3’s (35.2 feet vs. 36.5 feet).

The Kia K4 may be more efficient, handle and accelerate better because it weighs about 250 to 600 pounds less than the Audi S3.

The K4 Hatchback is 3 inches shorter than the S3, making the K4 easier to handle, maneuver and park in tight spaces.

Because it has more passenger and cargo room, the EPA rates the K4 a Mid-size car, while the S3 is rated a Subcompact.

The K4 has 11.7 cubic feet more passenger volume than the S3 (98.7 vs. 87).

The K4 Sedan has 2.2 inches more front headroom, 1.1 inches more front legroom, 1.7 inches more front shoulder room, .7 inches more rear headroom, 2.8 inches more rear legroom and 1.7 inches more rear shoulder room than the S3.

The K4 Sedan has a much larger trunk than the S3 (14.6 vs. 8.3 cubic feet).

The K4 GT-Line’s optional easy entry system glides the driver’s seat back when the door is unlocked or the ignition is switched off, making it easier for the driver to get in and out. The S3 doesn’t offer an easy entry system.

The K4’s standard Smart Key allows you to unlock the doors from either front door handle, open the trunk, and start the engine, all without removing the key from the pocket or purse. Keyless Engine Start/Stop standard on the S3 only offers hands-free access for the ignition, none to unlock the car.

The K4’s sun-visors swivel front-to-side to block glare from the side windows. The S3’s visors are fixed into the windshield header.

Optional air-conditioned seats in the K4 GT-Line keep the driver and front passenger comfortable and take the sting out of hot seats in Summer. The S3 doesn’t offer air-conditioned seats.

On extremely cold winter days, the K4 GT-Line’s optional heated steering wheel provides comfort, allowing the driver to steer safely and comfortably before the car heater warms up. The S3 doesn’t offer a heated steering wheel.

The Kia K4 comes in sedan and four door hatchback bodystyles; the Audi S3 isn’t available as a four door hatchback.

J.D. Power and Associates rated the K4 first among small cars in owner reported satisfaction. This includes how well the vehicle performs and satisfies its owner’s expectations. The S3 isn’t in the top three.

The Kia K4 outsold the Audi A3/S3/RS 3 by almost 17 to one during 2025.