VS
At a Glance
Power
335hp @ 5000
469hp @ 5500
Torque
368lb-ft @ 1600
516lb-ft @ 2250
Fuel
25 mpg est.
18 mpg est.
Engine
3.0 L/183ci
4.0 L/243ci
Choosing between the BMW 8 Series and the Mercedes-Benz Sl Class is one of the most common decisions car buyers in the United States face. The BMW 8 Series delivers 335hp @ 5000 while the Mercedes-Benz Sl Class produces 469hp @ 5500. On fuel, the 8 Series returns 25 mpg est. while the Sl Class uses 18 mpg est. — important in a market where fuel prices change monthly. Pricing starts at $94,500 for the 8 Series and $112,550 for the Sl Class. Both vehicles have their merits. The right choice depends on your priorities: fuel economy, performance, towing ability, safety features or total cost of ownership. This comparison covers every specification available so you can make an informed decision.
Specification
BMW 8 Series840i Convertible 2026 - From $94,500
Mercedes-Benz Sl ClassAMG SL 55 Roadster 2026 - From $112,550
Performance
Power Output (hp)
335hp @ 5000
469hp @ 5500
Torque (lb-ft)
368lb-ft @ 1600
516lb-ft @ 2250
Engine & Drivetrain
Engine Capacity
3.0 L/183ci
4.0 L/243ci
Engine Layout
Inline
—
Cylinders
6
8
Fuel Type
Gasoline
Gasoline
Forced Induction Device
Turbocharged
Turbocharged
Transmission
Automatic
Automatic
Number of Gears
8
—
Drive Wheels
Rear Wheel Drive
All Wheel Drive
Fuel Economy
Fuel Economy (Combined, est.)
25 mpg est.
18 mpg est.
Fuel Economy - City (mpg)
21mpg
14 (2025)mpg
Fuel Economy - Highway (mpg)
29mpg
21 (2025)mpg
Fuel Tank Capacity (gal)
18gal
18.5gal
Dimensions
Length (in)
191.1in
185.2in
Width (in)
74.9in
75.4in
Height (in)
52.7in
53.5in
Wheelbase (in)
111.1in
106.3in
Curb Weight (lbs)
4211lbs
4277lbs
Safety
ABS
✓ Standard
✓ Standard
Brake Assist
✓ Standard
✓ Standard
Stability Control
✓ Standard
✓ Standard
Traction Control
✓ Standard
✓ Standard
Driver Airbag
✓ Standard
✓ Standard
Passenger Airbag
✓ Standard
✓ Standard
Side Airbags Front
✓ Standard
✓ Standard
Curtain Airbags
—
✓ Standard
Features & Tech
Air Conditioning
✓ Standard
✓ Standard
Climate Control
✓ Standard
✓ Standard
Cruise Control
✓ Standard
✓ Standard
Adaptive Cruise Control
✓ Standard
✓ Standard
Bluetooth
✓ Standard
✓ Standard
Backup Camera
✓ Standard
✓ Standard
Rear Parking Aid
✓ Standard
✓ Standard
Heated Seats
✓ Standard
✓ Standard
Power Seat Adjustment
✓ Standard
✓ Standard
Keyless Entry
✓ Standard
✓ Standard
Alloy Wheels
✓ Standard
✓ Standard
The Verdict
Which Wins?
Overall Winner
BMW 8 Series
2 / 4 categories
Performance
Sl Class
Fuel Economy
8 Series
Value
8 Series
Practicality
Tied
Pros & Cons
BMW 8 Series
Better fuel economy (25 mpg est.)
Lower starting price ($94,500)
Few notable weaknesses
Mercedes-Benz Sl Class
Well-rounded specification
Higher fuel consumption (18 mpg est.)
Higher starting price
Frequently Asked Questions
Which is more fuel efficient, the 8 Series or Sl Class?
The 8 Series gets 25 mpg est. and the Sl Class gets 18 mpg est. on the combined cycle. The 8 Series is the more fuel-efficient choice. In real-world conditions with a mix of highway and urban driving, actual figures will be slightly higher.
Which has more power, the 8 Series or Sl Class?
The 8 Series produces 335hp @ 5000 and 368lb-ft @ 1600 of torque while the Sl Class delivers 469hp @ 5500 and 516lb-ft @ 2250 of torque. The Sl Class is the more powerful option.
What is the price difference between the 8 Series and Sl Class?
The 8 Series starts from $94,500 and the Sl Class from $112,550. The 8 Series is cheaper by $18,050 at this variant level. Final on-the-road pricing varies by dealer and specification.
Should I buy the 8 Series or the Sl Class?
It depends on your priorities. If fuel economy matters most, check the mpg figures above. If you need towing capacity, compare the towing ratings. For day-to-day driving - commutes, school runs and highway trips - consider ground clearance, service network coverage, and total cost of ownership including insurance and maintenance. Use the spec tables above to compare every detail before making your decision.
Also Consider