2025 Mercedes-Benz GLS-Class vs 2026 Audi RS 6
Comparison Overview
The 2025 Mercedes-Benz GLS-Class delivers opulent, traditional three-row luxury starting at a reasonable $89,200, powered by a potent 375 hp engine returning 21 MPG combined. Contrast this with the raw adrenaline surge of the 2026 Audi RS 6 Avant, a performance weapon masquerading as a wagon, commanding $130,700 for its staggering 621 hp. The RS 6 boasts nearly double the torque at 627 lb-ft, making the GLS’s 369 lb-ft feel reserved. While the GLS stretches 205.0 inches in length to accommodate its capacity, the RS 6 is significantly lower at 58.6 inches, reflecting its road-hugging ethos. This comparison pits the benchmark for ultimate luxury cruising against uncompromising, high-horsepower precision driving; the $41,500 gap defines the choice between serene comfort and track-ready exhilaration.
Size Comparison
Performance
Fuel Efficiency
Full Specifications
Our Verdicts
2025 Mercedes-Benz GLS-Class
The Mercedes-Benz GLS-Class offers superior fuel economy at 21 MPG combined, making daily driving less costly than the RS 6's 16 MPG.
2025 Mercedes-Benz GLS-Class
The GLS-Class, being a true three-row crossover at 71.8 inches tall, is inherently more practical for accommodating multiple passengers than the lower-riding RS 6 wagon.
2026 Audi RS 6
The Audi RS 6's immense output of 621 hp and 627 lb-ft of torque delivers a vastly superior, thrilling performance envelope.
2025 Mercedes-Benz GLS-Class
The Mercedes-Benz GLS-Class offers substantial luxury and capability for $41,500 less than the RS 6.
Choose the Mercedes-Benz GLS-Class if...
- You require genuine three-row utility and a height of 71.8 inches.
- Maximizing fuel economy, achieving 24 MPG on the highway, is a priority.
- You prioritize traditional, large-SUV comfort over outright, blistering performance.
Choose the Audi RS 6 if...
- You crave segment-leading power with 621 hp and 627 lb-ft of torque.
- You prefer the added utility of 29.9 cu ft of cargo space in a lower, more agile form factor.
- The premium driving dynamics justify the $130,700 MSRP.
Key Dimensions
| Dimension | Mercedes-Benz GLS-Class | Audi RS 6 |
|---|---|---|
| Length | 205.0" | 196.7" |
| Width | 79.9" | 76.8" |
| Height | 71.8" | 58.6" |
| Wheelbase | 123.4" | 115.3" |
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 | — | ✓ |
| Headlight Washers | — | ✓ |
| Front Integrated Headrests | — | ✓ |
| Rear Fixed 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 | 621 hp |
| Torque | 369 lb-ft @ 1800 rpm | 627 lb-ft |
| 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 | 14/21 MPG |
| EPA Fuel Economy (Combined) | 21 MPG | 16 MPG |
| EPA Driving Range (City/Highway) | 452.2/571.2 mi. | 270.2/405.3 mi. |
| Fuel Tank Capacity | 23.8 gal. | 19.3 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 | ✓ | ✓ |
| Cruise Control | — | ✓ |
| 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 | — |
| Speaker System | 13 | — |
| Subwoofer Count | 2 | — |
| 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. | 38.3 in. |
| Front Leg Room | 40.3 in. | 41.3 in. |
| Front Shoulder Room | 59.3 in. | 57.8 in. |
| Front Hip Room | 60.8 in. | — |
| Seat Material: Leatherette | ✓ | — |
| Front Seat Type: Bucket | ✓ | — |
| Driver Seat Power Adjustments | 10-way | 10-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 | 10-way |
| Passenger Seat Height Adjustment | ✓ | ✓ |
| Passenger Seat Lumbar Support | Power | Power |
| Passenger Seat Thigh Extension | ✓ | — |
| Passenger Seat Memory Settings | 3 | — |
| 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. | 39.5 in. |
| Rear Leg Room | 41.9 in. | 37.4 in. |
| Rear Shoulder Room | 58.5 in. | 56.5 in. |
| Rear Hip Room | 60.0 in. | — |
| Split-Folding Rear Seatback | ✓ | ✓ |
| Reclining Rear Seats | ✓ | — |
| Folding Center Armrest | ✓ | — |
| Power Folding Third Row Seat | ✓ | — |
| Folding Rear Seat Feature | — | ✓ |
| Pass-Thru Center Armrest | — | ✓ |
Tires and Wheels
| Feature | Mercedes-Benz | Audi |
|---|---|---|
| Wheel Material | Alloy | Alloy |
| Wheel Size | 21 x 11.0 in. | 21 in |
| Tire Type | All Season | Performance |
| Tire Size | 315/40R21 | 275/35R21 |
| Spare Tire Type | Temporary | — |
| Spare Tire Location | Inside Mounted | — |
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 6.
What is the primary trade-off when comparing the GLS-Class cargo space to the RS 6?
The Mercedes-Benz GLS-Class offers 17.4 cubic feet of cargo capacity, which is significantly less than the Audi RS 6's generous 29.9 cubic feet, despite the GLS being much longer overall.
How does the cost of ownership compare based on fuel requirements?
The GLS-Class is more economical for regular use, netting 21 MPG combined versus the RS 6's 16 MPG combined, meaning the RS 6 will require more frequent stops for premium unleaded fuel.
Is the massive power gap between the two vehicles noticeable in daily driving?
Yes, the 246 hp difference is vast; the RS 6 produces 621 hp, enabling vastly quicker acceleration metrics than the 375 hp output of the GLS-Class, emphasizing performance over the Benz's cruiser status.
Which vehicle has a more commanding presence based on dimensions?
The Mercedes-Benz GLS-Class has a larger footprint, measuring 205.0 inches long and 79.9 inches wide, compared to the slightly smaller, lower RS 6 wagon.
Do both vehicles use AWD and automatic transmissions?
Both the 2025 Mercedes-Benz GLS-Class and the 2026 Audi RS 6 utilize an All-Wheel Drive system and feature shiftable automatic transmissions (9-speed for the GLS, 8-speed for the RS 6).
What level of performance sacrifice is required to save $41,500?
Choosing the GLS saves $41,500 off the MSRP, but requires accepting 246 fewer horsepower and 258 fewer lb-ft of torque compared to the RS 6.
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