2025 Audi RS 6 vs 2025 Mercedes-Benz GLS-Class

$126,600 · Wagon

$89,200 · Crossover

Comparison Overview

The 2025 Audi RS 6 Wagon is an asphalt-devouring beast, launching with an intoxicating 621 hp and 627 lb-ft of torque, making its 14/21 MPG feel like a bargain for that performance pedigree. Contrast this sharply with the 2025 Mercedes-Benz GLS-Class, a commanding luxury crossover that prioritizes passenger comfort, offering a respectable 375 hp and a superior 21 MPG combined, all while sitting $37,400 lower in MSRP at $89,200. While the GLS-Class is notably larger at 205.0 inches long, the RS 6 maximizes usability with 30 cu ft of cargo space, demonstrating that performance doesn't entirely sacrifice utility. The RS 6 brings a serious 246 hp advantage over the GLS, firmly planting it in the ultra-performance segment, whereas the GLS focuses on hauling families with fewer compromises at the pump and a significantly lower entry price.

Size Comparison

Performance

Fuel Efficiency

Full Specifications

Our Verdicts

🚗 Best for Commuters

2025 Mercedes-Benz GLS-Class

The Mercedes-Benz GLS-Class offers better city fuel economy (19 MPG vs. 14 MPG) and a lower entry cost, making the daily grind less painful.

👨‍👩‍👧‍👦 Best for Families

2025 Mercedes-Benz GLS-Class

The GLS-Class is physically larger, offering superior cabin volume and better fuel efficiency for family road trips.

🏎️ Best for Enthusiasts

2025 Audi RS 6

The Audi RS 6's massive 621 hp and 627 lb-ft of torque deliver an unparalleled, visceral driving thrill that the GLS-Class cannot match.

💰 Best Value

2025 Mercedes-Benz GLS-Class

For $37,400 less, the GLS-Class provides sufficient power and luxury features appropriate for its segment.

Choose the Audi RS 6 if...

Your primary goal is explosive acceleration, as the RS 6 delivers 621 hp.
You need a practical vehicle but demand true supercar levels of speed and handling.
You prefer the lower, sleeker stance and maximum available utility cargo space of 30 cu ft.

Choose the Mercedes-Benz GLS-Class if...

Budget is a significant factor, as the GLS-Class undercuts the RS 6 by $37,400.
Fuel efficiency matters, with the GLS netting 4 MPG more combined (21 MPG vs. 17 MPG).
You require a larger footprint, as the GLS is substantially taller at 71.8 inches.

Key Dimensions

Dimension	Audi RS 6	Mercedes-Benz GLS-Class
Length	196.7"	205.0"
Width	76.8"	79.9"
Height	58.6"	71.8"
Wheelbase	115.3"	123.4"

Features Comparison

Safety

Feature	Audi	Mercedes-Benz
Lane Departure Warning	✓	✓
Pre-Collision Safety System	✓	✓
Post-Collision Safety System	✓	✓
Dual Front Side-Mounted Airbags	✓	✓
Dual Rear Side-Mounted Airbags	✓	—
Front Head Airbags	✓	✓
Rear Head Airbags	✓	✓
Passenger Airbag Occupant Sensing Deactivation	✓	✓
Electronic Stability Control	✓	✓
Traction Control System	✓	✓
LATCH System	✓	✓
Rear Door Child Safety Locks	✓	✓
Anti-lock Brakes (ABS)	4-Wheel	4-Wheel
Front Ventilated Disc Brakes	✓	✓
Rear Ventilated Disc Brakes	✓	✓
Brake Assist	✓	✓
Tire Pressure Monitoring System	✓	✓
Automatic Headlights	✓	✓
Headlight Delay-Off	✓	✓
LED Headlights	✓	✓
Daytime Running Lights	✓	✓
Headlight Washers	✓	—
Integrated Turn Signal Mirrors	✓	✓
Front Headrests	2	2
Front Integrated Headrests	✓	—
Rear Headrests	3	3
Rear Height Adjustable Headrests	✓	✓
Rear Center 3-Point Seatbelt	✓	✓
Anti-Theft Alarm System (Remote)	✓	✓
Engine Immobilizer	✓	✓
Blind Spot Monitor	—	✓
Lane Keeping Assist System	—	✓
Front Cross Traffic Alert	—	✓
Rear Cross Traffic Alert	—	✓
Driver Attention Alert	—	✓
Third Row Head Airbags	—	✓
Brake Drying	—	✓
Brake Preparation System	—	✓
Adaptive Headlights	—	✓
Cornering Lights	—	✓
Front Power Adjustable Headrests	—	✓

Engine

Feature	Audi	Mercedes-Benz
Base Engine Displacement	4.0 L	3.0 L
Number of Cylinders	V8	inline 6
Base Engine Type	mild hybrid	mild hybrid
Horsepower	621 hp	375 hp @ 5800 rpm
Torque	627 lb-ft	369 lb-ft @ 1800 rpm
Number of Valves	32	24
Camshaft Type	Double overhead cam (DOHC)	Double overhead cam (DOHC)
Variable Valve Timing	Variable	Variable
Fuel Injection Type	✓	✓

Drive Train

Feature	Audi	Mercedes-Benz
Transmission Type	8-speed shiftable automatic	9-speed shiftable automatic
Drivetrain Type	all wheel drive	all wheel drive
[object Object]	✓	—
[object Object]	✓	—
Center Differential Type	—	Limited Slip
Hill Descent Control	—	✓

Fuel

Feature	Audi	Mercedes-Benz
Fuel Type	premium unleaded (required)	premium unleaded (required)
EPA Fuel Economy (City/Highway)	14/21 MPG	19/24 MPG
EPA Fuel Economy (Combined)	17 MPG	21 MPG
EPA Driving Range (City/Highway)	270.2/405.3 mi.	452.2/571.2 mi.
Fuel Tank Capacity	19.3 gal.	23.8 gal.

Comfort & Convenience

Feature	Audi	Mercedes-Benz
Push Button Start	✓	✓
Power Tilt and Telescopic Steering Wheel	✓	✓
Transmission Controls on Steering Wheel	✓	✓
Audio Controls on Steering Wheel	✓	✓
Electric Power Steering	✓	✓
Front View Camera	✓	✓
Side View Camera	✓	✓
Rear View Camera	✓	✓
Front Parking Sensors	✓	✓
Rear Parking Sensors	✓	✓
Wireless Charging Pad	✓	✓
Cruise Control	✓	—
Universal Remote Transmitter	✓	✓
Front Cupholders	✓	✓
Rear Cupholders	✓	✓
Front Door Pockets	✓	✓
Rear Door Pockets	✓	✓
Front Seatback Storage	✓	✓
Leather Steering Wheel	✓	✓
Heated Steering Wheel	✓	—
Four Zone Climate Control	✓	✓
Rear Ventilation Ducts with Fan Control	✓	✓
Interior Air Filtration	✓	✓
Dual Vanity Mirrors	✓	✓
Auto-Dimming Rearview Mirror	✓	✓
Turn Signal Indicators in Mirrors	✓	✓
Cruise Control on Steering Wheel	—	✓
Automatic Parking Assist	—	✓
Adaptive Cruise Control	—	✓
3rd Row Cupholders	—	✓
Overhead Console with Storage	—	✓
Power Rear Seat Easy Entry	—	✓

In Car Entertainment

Feature	Audi	Mercedes-Benz
Infotainment Display	10.1 in	12.3 in
AM/FM Stereo	✓	✓
Premium Brand Speakers	Bang & Olufsen	—
Surround Audio	Discrete	Discrete
Android Auto (Wireless)	✓	✓
Apple CarPlay (Wireless)	✓	✓
USB Port	✓	✓
USB Port with External Media Control	✓	✓
Satellite Radio	✓	✓
Satellite Radio Trial Period	3 months	6 months
Premium Speaker Brand	—	Burmester
Stereo Power	—	590W
Speaker System	—	13
Subwoofer Count	—	2
Speed Sensitive Volume Control	—	✓

Power Feature

Feature	Audi	Mercedes-Benz
One-Touch Power Windows	4	4
Moonroof Type	1st Row Power Glass Extended	1st Row Power Glass Extended
Keyless Entry	✓	✓
Heated Mirrors	✓	✓
Reverse Tilt Passenger Mirror	—	✓

Frontseats

Feature	Audi	Mercedes-Benz
Front Head Room	38.3 in.	39.4 in.
Front Leg Room	41.3 in.	40.3 in.
Front Shoulder Room	57.8 in.	59.3 in.
Seat Material: Premium Leather	✓	—
Front Seat Type: Sport	✓	—
Driver Seat Power Adjustments	10-way	10-way
Driver Seat Height Adjustment	✓	✓
Driver Seat Lumbar Support	Power	Power
Driver Seat Memory Settings	2	3
Passenger Seat Power Adjustments	10-way	10-way
Passenger Seat Height Adjustment	✓	✓
Passenger Seat Lumbar Support	Power	Power
Driver Seat Heating	Multi-level	Multi-level
Passenger Seat Heating	Multi-level	Multi-level
Driver Seat Ventilation	✓	✓
Passenger Seat Ventilation	✓	✓
Front Hip Room	—	60.8 in.
Seat Material: Leatherette	—	✓
Front Seat Type: Bucket	—	✓
Driver Seat Thigh Extension	—	✓
Passenger Seat Thigh Extension	—	✓
Passenger Seat Memory Settings	—	3

Rearseats

Feature	Audi	Mercedes-Benz
Rear Head Room	39.5 in.	40.2 in.
Rear Leg Room	37.4 in.	41.9 in.
Rear Shoulder Room	56.5 in.	58.5 in.
Split-Folding Rear Seatback	✓	✓
Folding Rear Seat Feature	✓	—
Pass-Thru Center Armrest	✓	—
Rear Hip Room	—	60.0 in.
Reclining Rear Seats	—	✓
Folding Center Armrest	—	✓
Power Folding Third Row Seat	—	✓

Tires and Wheels

Feature	Audi	Mercedes-Benz
Wheel Material	Alloy	Alloy
Wheel Size	21 in	21 x 11.0 in.
Tire Type	Performance	All Season
Tire Size	275/35R21	315/40R21
Spare Tire Type	—	Temporary
Spare Tire Location	—	Inside Mounted

Suspension

Feature	Audi	Mercedes-Benz
Four-Wheel Independent Suspension	✓	✓
Front Stabilizer Bar	✓	✓
Rear Stabilizer Bar	✓	✓

Warranty

Feature	Audi	Mercedes-Benz
Basic Warranty	4 yr./ 50000 mi.	4 yr./ 50000 mi.
Drivetrain Warranty	4 yr./ 50000 mi.	4 yr./ 50000 mi.
Corrosion/Rust Warranty	12 yr./ unlimited mi.	4 yr./ 50000 mi.
Roadside Assistance	4 yr./ unlimited mi.	4 yr./ 50000 mi.
Hybrid Component Warranty	—	6 yr./ 62000 mi.

Frequently Asked Questions

Common questions about comparing the 2025 Audi RS 6 and 2025 Mercedes-Benz GLS-Class.

What is the performance gap between the 2025 Audi RS 6 and the Mercedes-Benz GLS-Class?

The Audi RS 6 is significantly more potent, boasting 621 hp and 627 lb-ft of torque, which is 246 horsepower more than the GLS-Class’s 375 hp. This power difference defines the RS 6 as a high-performance machine while the GLS focuses on smooth, ample cruising capability.

How does the cargo capacity compare given the size difference?

Despite the GLS-Class being a much taller and longer vehicle (205.0 inches long versus the RS 6's 196.7 inches), the Audi RS 6 actually offers more usable space with 30 cubic feet compared to the GLS-Class’s 17.4 cubic feet.

Is the premium fuel requirement similar for both models?

Yes, both the 2025 Audi RS 6 and the 2025 Mercedes-Benz GLS-Class require premium unleaded fuel for optimal operation. However, the RS 6's thirst results in a combined 17 MPG, while the GLS manages 21 MPG combined.

Which vehicle is better suited for long highway drives based on MPG?

The Mercedes-Benz GLS-Class is the more economical choice for long hauls, achieving 24 Highway MPG compared to the RS 6’s 21 Highway MPG. This 3 MPG difference can result in substantial savings over frequent driving.

Which vehicle has the higher initial purchase price?

The 2025 Audi RS 6 carries a significantly higher entry price of $126,600. This is $37,400 more expensive than the base MSRP for the 2025 Mercedes-Benz GLS-Class, which starts at $89,200.

Do the transmissions differ significantly between these two AWD vehicles?

They use different setups; the RS 6 employs an 8-speed shiftable automatic transmission geared for aggressive shifting. In contrast, the GLS-Class uses a 9-speed shiftable automatic, often prioritizing smoother, more fuel-conscious shifts.