2019 Porsche 911 vs. 2019 Mercedes SLC

Detailed Review, Specifications & Comparison

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The 911 has a standard automatic post-collision braking system, which automatically applies the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The SLC doesn’t offer a post collision braking system: in the event of a collision that triggers the airbags, more collisions are possible without the protection of airbags that may have already deployed.

The 911 offers all-wheel drive to maximize traction under poor conditions, especially in ice and snow. The SLC doesn’t offer all-wheel drive.

Both the 911 and the SLC have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front seatbelt pretensioners, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, daytime running lights, rearview cameras, available crash mitigating brakes and blind spot warning systems.


The 911’s corrosion warranty is 7 years longer than the SLC’s (12 vs. 5 years).


J.D. Power and Associates’ 2018 Initial Quality Study of new car owners surveyed provide the statistics that show that Porsche vehicles are better in initial quality than Mercedes vehicles. J.D. Power ranks Porsche fourth in initial quality, above the industry average. With 13 more problems per 100 vehicles, Mercedes is ranked 14th.

J.D. Power and Associates’ 2018 survey of the owners of three-year-old vehicles provides the long-term dependability statistics that show that Porsche vehicles are more reliable than Mercedes vehicles. J.D. Power ranks Porsche second in reliability, above the industry average. With 47 more problems per 100 vehicles, Mercedes is ranked 15th.

From surveys of all its subscribers, Consumer Reports’ December 2018 Auto Issue reports that Porsche vehicles are more reliable than Mercedes vehicles. Consumer Reports ranks Porsche 6 places higher in reliability than Mercedes.


The 911 has more powerful engines than the SLC:




911 3.0 turbo 6 cyl.

370 HP

331 lbs.-ft.

911 S 3.0 turbo 6 cyl.

420 HP

368 lbs.-ft.

911 GTS 3.0 turbo 6 cyl.

450 HP

405 lbs.-ft.

911 GT3 4.0 DOHC 6 cyl.

500 HP

339 lbs.-ft.

911 GT3 RS 4.0 DOHC 6 cyl.

520 HP

346 lbs.-ft.

911 Turbo 3.8 turbo 6 cyl.

540 HP

523 lbs.-ft.

911 Turbo S 3.8 turbo 6 cyl.

580 HP

553 lbs.-ft.

911 Turbo S Exclusive Series 3.8 turbo 6 cyl.

607 HP

553 lbs.-ft.

911 GT2 RS 3.8 turbo 6 cyl.

700 HP

553 lbs.-ft.

SLC 300 2.0 turbo 4 cyl.

241 HP

273 lbs.-ft.

AMG SLC 43 3.0 turbo V6

362 HP

384 lbs.-ft.

AMG SLC 43 3.0 turbo V6

385 HP

384 lbs.-ft.

The flat cylinder configuration of the boxer engine in the 911 lowers its center of gravity, enhancing handling stability. The SLC doesn’t offer a boxer engine configuration.

Fuel Economy and Range

On the EPA test cycle the 911 S RWD Auto 3.0 twin turbo 6 cyl. (420 HP) gets better city fuel mileage than the AMG SLC 43 3.0 twin turbo V6 (362 HP) (22 city vs. 20 city).

Regenerative brakes improve the 911’s fuel efficiency by converting inertia back into energy instead of wasting it. The SLC doesn’t offer a regenerative braking system.

The 911 RWD’s standard fuel tank has a gallon more fuel capacity than the SLC’s standard fuel tank (16.9 vs. 15.9 gallons), for longer range between fill-ups. The 911 4/GTS/GT3’s standard fuel tank has 1.7 gallons more fuel capacity than the SLC’s standard fuel tank (17.6 vs. 15.9 gallons). The 911 GT2 RS’ optional fuel tank has 5.2 gallons more fuel capacity than the SLC AMG’s standard fuel tank (23.7 vs. 18.5 gallons).

Transmission and Drivetrain

The 911 offers a manual transmission for better acceleration, control and fuel economy. The SLC doesn’t offer a manual transmission.

The 911 offers an optional sequential manual gearbox (SMG). With no clutch pedal to worry about and a fully automatic mode, an SMG is much more efficient than a conventional automatic but just as easy to drive. The SLC doesn’t offer an SMG.

All-wheel drive, available in the 911, provides the best traction for acceleration in wet, dry, and icy conditions. In corners, all-wheel drive allows both outside wheels to provide power, balancing the car. This allows for better handling. The Mercedes SLC is not available with all-wheel drive.

The 911 PDK’s optional launch control uses engine electronics to hold engine RPM’s precisely in order to provide the most stable and rapid acceleration possible, using all of the available traction. The SLC doesn’t offer launch control.

Brakes and Stopping

For better stopping power the 911’s brake rotors are larger than those on the SLC:




SLC 300


Front Rotors

13 inches

16.1 inches

12.7 inches

14.2 inches

Rear Rotors

13 inches

15.4 inches

11.8 inches

13 inches

The 911’s standard front and rear disc brakes are vented to help dissipate heat for shorter stops with less fading. The rear discs standard on the SLC 300 are solid, not vented.

The 911 offers optional heat-treated ceramic brake rotors, which last ten to twenty times as long as conventional cast iron rotors, don’t rust, don’t fade during repeated high speed braking, and their lighter weight contribute to better braking, handling and acceleration. The SLC doesn’t offer ceramic brake rotors.

Tires and Wheels

For better traction, the 911 has larger standard tires than the SLC (F:235/40R19 & R:295/35R19 vs. F:225/45R17 & R:245/40R17). The 911 GT2 RS/GT3 RS’ tires are larger than the largest tires available on the SLC (F:265/35R20 & R:325/30R21 vs. F:235/40R18 & R:255/35R18).

The 911’s standard 235/40R19 front and 295/35R19 rear tires provide better handling because they have a lower 40 series front and 35 series rear profile (height to width ratio) that provides a stiffer sidewall than the SLC 300’s standard 45 series front and 40 series rear tires. The 911’s optional 245/35R20 front and 305/30R20 rear tires have a lower 35 series front and 30 series rear profile than the SLC’s optional 40 series front and 35 series rear tires.

For better ride, handling and brake cooling the 911 has standard 19-inch wheels. Smaller 17-inch wheels are standard on the SLC 300. The 911 GT2 RS/GT3 RS’ 20-inch front and 21-inch rear wheels are larger than the 18-inch wheels optional on the SLC.

Suspension and Handling

The 911 offers active sway bars, which help keep it flat and controlled during cornering, but disconnect at lower speeds to smooth the ride and offer greater off-road suspension articulation. This helps keep the tires glued to the road on-road and off. The SLC doesn’t offer an active sway bar system.

The 911 has a standard automatic front and rear load leveling suspension to keep ride height level with a heavy load or when towing. The SLC doesn’t offer a load leveling suspension.

For better maneuverability, the 911 GT2 RS’ turning circle is .9 feet tighter than the SLC’s (33.6 feet vs. 34.5 feet).


The design of the Porsche 911 amounts to more than styling. The 911 offers aerodynamic coefficients of drag from .29 to .32 Cd (depending on bodystyle and options). That is lower than the SLC (.33 to .36). A more efficient exterior helps the 911 go faster and keeps the interior quieter. It also helps the 911 get better fuel mileage.

The front grille of the 911 uses electronically controlled shutters to close off airflow and reduce drag when less engine cooling is needed. This helps improve highway fuel economy. The SLC doesn’t offer active grille shutters.

Passenger Space

The 911 has standard seating for 4 passengers; the SLC can only carry 2.

The 911 Cabriolet has 19.2 cubic feet more passenger volume than the SLC (68 vs. 48.8).

Servicing Ease

J.D. Power and Associates surveys of service recipients show that Porsche service is better than Mercedes. J.D. Power ranks Porsche second in service department satisfaction. With a 6% lower rating, Mercedes is ranked 6th.


The 911’s instruments include an oil pressure gauge and a temperature gauge – which could save your engine! Often ‘idiot lights’ don’t warn you until damage has been done. The SLC does not have an oil pressure gauge.

The 911’s front and rear power windows all open or close with one touch of the switches, making it more convenient at drive-up windows and toll booths, or when talking with someone outside of the car. The SLC’s rear power window switches have to be held the entire time to close them fully.

Optional air-conditioned seats in the 911 keep the driver and front passenger comfortable and take the sting out of hot seats in summer. The SLC doesn’t offer air-conditioned seats.

On extremely cold winter days, the 911’s optional heated steering wheel provides comfort, allowing the driver to steer safely and comfortably before the car heater warms up. The SLC doesn’t offer a heated steering wheel.

The 911 has a standard dual zone air conditioning allows the driver and front passenger to choose two completely different temperatures so people with different temperature preferences won’t have to compromise. This makes both the driver and front passenger as comfortable as possible. Dual zone air conditioning costs extra on the SLC.

Model Availability

The Porsche 911 comes in coupe and convertible bodystyles; the Mercedes SLC isn’t available as a coupe.

Economic Advantages

The 911 will cost the buyer less in the long run because of its superior resale value. The IntelliChoice estimates that the 911 will retain 52.12% to 58.08% of its original price after five years, while the SLC only retains 44.39% to 47.67%.


Consumer Reports® recommends the Porsche 911, based on reliability, safety and performance.

J.D. Power and Associates rated the 911 first among midsize premium sporty cars in owner reported satisfaction. This includes how well the vehicle performs and satisfies its owner’s expectations. The SLC isn’t in the top three in its category.

The 911 Carrera GTS was chosen as one of Automobile Magazine’s “All Stars” in 2018. The SLC has never been an “All Star.”

The Porsche 911 outsold the Mercedes SLC by almost five to one during 2018.

© 1991-2018 Advanta-STAR Automotive Research. All rights reserved.

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