2025 Mercedes-Benz GLS-Class vs 2026 Audi RS Q8

$89,200 · Crossover

$138,300 · Crossover

Comparison Overview

The most significant numerical disparity between the 2025 Mercedes-Benz GLS-Class (Car1) and the 2026 Audi RS Q8 (Car2) is the Manufacturer's Suggested Retail Price (MSRP), showing a $49,100 premium for the Audi at $138,300 versus the GLS-Class's $89,200. This price gap reflects the RS Q8's superior performance metrics, boasting 631 hp and 627 lb-ft of torque compared to the GLS-Class’s 375 hp and 369 lb-ft. However, this power comes at a cost to efficiency; the GLS-Class achieves 21 combined MPG, substantially better than the RS Q8’s 16 combined MPG. Furthermore, dimensional analysis reveals the GLS-Class is longer at 205.0 inches and significantly taller at 71.8 inches, while the RS Q8 offers nearly double the standard cargo capacity at 33 cu ft versus the GLS's 17.4 cu ft.

Size Comparison

Performance

Fuel Efficiency

Full Specifications

Our Verdicts

🚗 Best for Commuters

2025 Mercedes-Benz GLS-Class

The GLS-Class wins for commuters due to its superior fuel economy of 21 combined MPG, which is 5 MPG better than the RS Q8.

👨‍👩‍👧‍👦 Best for Families

2026 Audi RS Q8

The RS Q8 provides substantially more usable space, offering 33 cu ft of cargo capacity compared to the GLS-Class's 17.4 cu ft.

🏎️ Best for Enthusiasts

2026 Audi RS Q8

The RS Q8 clearly leads in performance metrics, generating 631 hp and 627 lb-ft of torque, eclipsing the GLS-Class's 375 hp.

💰 Best Value

2025 Mercedes-Benz GLS-Class

The GLS-Class offers superior overall value given its $89,200 MSRP provides 375 hp, representing a much lower cost per horsepower metric.

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

Your primary concern is minimizing running costs, benefiting from the 21 combined MPG rating.
You require the maximum vertical clearance, as the GLS-Class stands taller at 71.8 inches.
The base price of $89,200 fits comfortably within a strict budget, being $49,100 less than the competitor.

Choose the Audi RS Q8 if...

Maximum acceleration and power output are non-negotiable, evidenced by its 631 hp.
You prioritize maximum luggage space, as the RS Q8 provides 33 cu ft versus Car1's 17.4 cu ft.
You prefer a more compact overall footprint, with the RS Q8 measuring 197.7 inches in length compared to 205.0 inches for Car1.

Key Dimensions

Dimension	Mercedes-Benz GLS-Class	Audi RS Q8
Length	205.0"	197.7"
Width	79.9"	79.0"
Height	71.8"	67.5"
Wheelbase	123.4"	117.9"

Features Comparison

Safety

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

Engine

Feature	Mercedes-Benz	Audi
Base Engine Displacement	3.0 L	4.0 L
Number of Cylinders	inline 6	V8
Base Engine Type	mild hybrid	mild hybrid
Horsepower	375 hp @ 5800 rpm	631 hp @ 6000 rpm
Torque	369 lb-ft @ 1800 rpm	627 lb-ft @ 2300 rpm
Number of Valves	24	32
Camshaft Type	Double overhead cam (DOHC)	Double overhead cam (DOHC)
Variable Valve Timing	Variable	Variable
Fuel Injection Type	✓	✓

Drive Train

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

Fuel

Feature	Mercedes-Benz	Audi
Fuel Type	premium unleaded (required)	premium unleaded (required)
EPA Fuel Economy (City/Highway)	19/24 MPG	14/20 MPG
EPA Fuel Economy (Combined)	21 MPG	16 MPG
EPA Driving Range (City/Highway)	452.2/571.2 mi.	315.0/450.0 mi.
Fuel Tank Capacity	23.8 gal.	22.5 gal.

Comfort & Convenience

Feature	Mercedes-Benz	Audi
Push Button Start	✓	✓
Power Tilt and Telescopic Steering Wheel	✓	✓
Transmission Controls on Steering Wheel	✓	✓
Cruise Control 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	✓	—
Automatic Parking Assist	✓	—
Wireless Charging Pad	✓	✓
Adaptive Cruise Control	✓	✓
Universal Remote Transmitter	✓	✓
Front Cupholders	✓	✓
Rear Cupholders	✓	✓
3rd Row Cupholders	✓	—
Front Door Pockets	✓	✓
Rear Door Pockets	✓	✓
Overhead Console with Storage	✓	—
Front Seatback Storage	✓	✓
Power Rear Seat Easy Entry	✓	—
Leather 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	✓	✓
Rear Parking Sensors with Side Sensing	—	✓
Heated Steering Wheel	—	✓

In Car Entertainment

Feature	Mercedes-Benz	Audi
Infotainment Display	12.3 in	10.1 in
AM/FM Stereo	✓	✓
Premium Speaker Brand	Burmester	—
Stereo Power	590W	730W
Speaker System	13	17
Subwoofer Count	2	1
Surround Audio	Discrete	Discrete
Android Auto (Wireless)	✓	✓
Apple CarPlay (Wireless)	✓	✓
USB Port	✓	✓
USB Port with External Media Control	✓	✓
Satellite Radio	✓	✓
Satellite Radio Trial Period	6 months	3 months
Speed Sensitive Volume Control	✓	—
Premium Brand Speakers	—	Bang & Olufsen

Power Feature

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

Frontseats

Feature	Mercedes-Benz	Audi
Front Head Room	39.4 in.	37.1 in.
Front Leg Room	40.3 in.	41.3 in.
Front Shoulder Room	59.3 in.	59.5 in.
Front Hip Room	60.8 in.	—
Seat Material: Leatherette	✓	—
Front Seat Type: Bucket	✓	—
Driver Seat Power Adjustments	10-way	8-way
Driver Seat Height Adjustment	✓	✓
Driver Seat Lumbar Support	Power	Power
Driver Seat Thigh Extension	✓	—
Driver Seat Memory Settings	3	2
Passenger Seat Power Adjustments	10-way	8-way
Passenger Seat Height Adjustment	✓	✓
Passenger Seat Lumbar Support	Power	Power
Passenger Seat Thigh Extension	✓	—
Passenger Seat Memory Settings	3	2
Driver Seat Heating	Multi-level	Multi-level
Passenger Seat Heating	Multi-level	Multi-level
Driver Seat Ventilation	✓	✓
Passenger Seat Ventilation	✓	✓
Seat Material: Premium Leather	—	✓
Front Seat Type: Sport	—	✓

Rearseats

Feature	Mercedes-Benz	Audi
Rear Head Room	40.2 in.	38.1 in.
Rear Leg Room	41.9 in.	40.2 in.
Rear Shoulder Room	58.5 in.	58.4 in.
Rear Hip Room	60.0 in.	—
Split-Folding Rear Seatback	✓	✓
Reclining Rear Seats	✓	✓
Folding Center Armrest	✓	✓
Power Folding Third Row Seat	✓	—

Tires and Wheels

Feature	Mercedes-Benz	Audi
Wheel Material	Alloy	Alloy
Wheel Size	21 x 11.0 in.	—
Tire Type	All Season	Performance
Tire Size	315/40R21	295/40R22
Spare Tire Type	Temporary	—
Spare Tire Location	Inside Mounted	—
Wheel Diameter	—	22 in

Suspension

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

Warranty

Feature	Mercedes-Benz	Audi
Basic Warranty	4 yr./ 50000 mi.	4 yr./ 50000 mi.
Drivetrain Warranty	4 yr./ 50000 mi.	4 yr./ 50000 mi.
Hybrid Component Warranty	6 yr./ 62000 mi.	—
Corrosion/Rust Warranty	4 yr./ 50000 mi.	12 yr./ unlimited mi.
Roadside Assistance	4 yr./ 50000 mi.	4 yr./ unlimited mi.
Complimentary Scheduled Maintenance	—	3 yr./ 30000 mi.

Frequently Asked Questions

Common questions about comparing the 2025 Mercedes-Benz GLS-Class and 2026 Audi RS Q8.

What is the main operational cost difference between the 2025 GLS-Class and the 2026 RS Q8?

The operational cost difference is substantial, primarily driven by fuel consumption. The Mercedes-Benz GLS-Class achieves 21 combined MPG, whereas the Audi RS Q8 is rated for only 16 combined MPG, representing a significant difference in required fuel volume over time.

How does the difference in horsepower translate to real-world driving?

The RS Q8's 256 hp advantage (631 hp vs. 375 hp) suggests drastically faster acceleration metrics, typical of a performance-oriented vehicle. While the GLS-Class offers adequate power, the RS Q8 is built explicitly for superior speed metrics.

Is the higher MSRP of the Audi RS Q8 justified by its size difference compared to the GLS-Class?

No, the Audi RS Q8 has a lower MSRP but is physically smaller in overall length and height, yet offers significantly more cargo volume (33 cu ft vs 17.4 cu ft). The price premium is driven by powertrain enhancements, not greater external size.

Do both vehicles require premium unleaded fuel?

Yes, both the 2025 Mercedes-Benz GLS-Class and the 2026 Audi RS Q8 specify that premium unleaded fuel is required for operation.

How much more cargo space does the RS Q8 offer over the GLS-Class?

The 2026 Audi RS Q8 offers 33 cubic feet of cargo capacity, which is 15.6 cubic feet more than the 2025 Mercedes-Benz GLS-Class’s 17.4 cubic feet, making it vastly superior for hauling luggage.

Which vehicle offers a smoother shifting experience with its standard automatic transmission?

The Mercedes-Benz GLS-Class utilizes a 9-speed shiftable automatic transmission, potentially offering smoother, closer ratio changes than the 8-speed shiftable automatic transmission standard in the Audi RS Q8.