2019 Acura RLX vs. 2019 Mercedes CLS

Detailed Review, Specifications & Comparison

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

For its top level performance in all IIHS frontal, side, rear impact and roof-crush tests, its standard front crash prevention system, and its headlight’s “Acceptable” rating, the Insurance Institute for Highway Safety grants the RLX the rating of “Top Pick” for 2018, a rating granted to only 100 vehicles tested by the IIHS. The CLS has not been tested, yet.


Acura’s powertrain warranty covers the RLX 2 years and 20,000 miles longer than Mercedes covers the CLS. Any repair needed on the engine, transmission, axles, joints or driveshafts is fully covered for 6 years or 70,000 miles. Coverage on the CLS ends after only 4 years or 50,000 miles.


The engines in the RLX have a single overhead cam for simplicity. The engines in the CLS have dual overhead cams, which add to the number of moving parts and the complexity of the cylinder heads.

From surveys of all its subscribers, Consumer Reports’ December 2018 Auto Issue reports that Acura vehicles are more reliable than Mercedes vehicles. Consumer Reports ranks Acura 4 places higher in reliability than Mercedes.


The RLX Sport Hybrid’s standard 3.5 SOHC V6 hybrid produces 15 more horsepower (377 vs. 362) than the CLS 450’s standard 3.0 turbo 6 cyl. hybrid.

Fuel Economy and Range

On the EPA test cycle the RLX Sport Hybrid gets better fuel mileage than the CLS 450 4MATIC (28 city/29 hwy vs. 23 city/30 hwy).

An engine control system that can shut down half of the engine’s cylinders helps improve the RLX’s fuel efficiency. The CLS doesn’t offer a system that can shut down part of the engine.

The RLX has a standard cap-less fueling system. The fuel filler is automatically opened when the fuel nozzle is inserted and automatically closed when it’s removed. This eliminates the need to unscrew and replace the cap and it reduces fuel evaporation, which causes pollution. The CLS doesn’t offer a cap-less fueling system.


A 10-speed automatic is standard on the Acura RLX V6, for better acceleration and lower engine speed on the highway. Only a nine-speed automatic is available for the CLS.

The RLX offers a standard 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 CLS doesn’t offer an SMG or a conventional manual transmission.

Brakes and Stopping

The RLX stops shorter than the CLS:





70 to 0 MPH

166 feet

167 feet

Car and Driver

60 to 0 MPH

112 feet

117 feet

Motor Trend

Suspension and Handling

The RLX has standard front and rear gas-charged shocks for better control over choppy roads. The CLS’ suspension doesn’t offer gas-charged shocks.


The RLX uses computer-generated active noise cancellation to help remove annoying noise and vibration from the passenger compartment, especially at low frequencies. The CLS doesn’t offer active noise cancellation.

Passenger Space

Because it has more passenger and cargo room, the EPA rates the RLX a Mid-size car, while the CLS is rated a Compact.

The RLX has 9.1 cubic feet more passenger volume than the CLS (102.1 vs. 93).

The RLX has .7 inches more front headroom, .4 inches more front legroom, 1.8 inches more front shoulder room, 1 inch more rear headroom, 3.8 inches more rear legroom and .5 inches more rear shoulder room than the CLS.

Cargo Capacity

The RLX has a much larger trunk than the CLS (14.9 vs. 11.9 cubic feet).

Economic Advantages

Insurance will cost less for the RLX owner. The Complete Car Cost Guide estimates that insurance for the RLX will cost $1375 to $11818 less than the CLS over a five-year period.

IntelliChoice estimates that five-year ownership costs (depreciation, financing, insurance, fuel, fees, repairs and maintenance) for the Acura RLX will be $24595 to $41761 less than for the Mercedes CLS.


The Acura RLX outsold the Mercedes CLS by over two to one during 2018.

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

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