The RLX's pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The Cadenza doesn't offer pre-crash pretensioners.

The RLX has standard whiplash protection, which use a specially designed headrest to protect the driver and front passenger from whiplash. During a rear-end collision, the whiplash protection system moves the headrests forward to prevent neck and spine injuries. The Cadenza doesn't offer a whiplash protection system.

The RLX Sport Hybrid has all-wheel drive to maximize traction under poor conditions, especially in ice and snow. The Cadenza doesn't offer all-wheel drive.

The Acura RLX has Daytime Running Lights to help keep it more visible under all conditions. Canadian government studies show that driving with lights during the day reduces accidents by 11% by making vehicles more conspicuous. The Cadenza doesn't offer Daytime Running Lights.

Both the RLX and the Cadenza have standard driver and passenger frontal airbags, front side-impact airbags, driver knee airbags, side-impact head airbags, front seatbelt pretensioners, front wheel drive, height-adjustable front shoulder belts, plastic fuel tanks, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, rearview cameras and available around view monitors.

The RLX's 5 year corrosion warranty has no mileage limitations, but the corrosion warranty on the Cadenza runs out after 100,000 miles.

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

A reliable vehicle saves its owner time, money and trouble. Nobody wants to be stranded or have to be without a vehicle while it's being repaired. Consumer Reports rates the RLX's reliability 34 points higher than the Cadenza.

The RLX's standard 3.5 SOHC V6 produces 20 more horsepower (310 vs. 290) and 19 lbs.-ft. more torque (272 vs. 253) than the Cadenza's 3.3 DOHC V6. The RLX Sport Hybrid's standard 3.5 SOHC V6 hybrid produces 87 more horsepower (377 vs. 290) and 88 lbs.-ft. more torque (341 vs. 253) than the Cadenza's 3.3 DOHC V6.

On the EPA test cycle the RLX FWD V6 gets better highway fuel mileage than the Cadenza (20 city/29 hwy vs. 20 city/27 hwy).

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

Regenerative brakes improve the RLX Sport Hybrid's fuel efficiency by converting inertia back into energy instead of wasting it. The Cadenza doesn't offer a regenerative braking system.

In heavy traffic or at stoplights the RLX Sport Hybrid's engine automatically turns off when the vehicle is stopped, saving fuel and reducing pollution. The engine is automatically restarted when the driver gets ready to move again. (Start/Stop isn't accounted in present EPA fuel mileage tests.) The Cadenza doesn't offer an automatic engine start/stop system.

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 Cadenza doesn't offer a cap-less fueling system.

A ten-speed automatic is standard on the Acura RLX V6, for better acceleration and lower engine speed on the highway. Only an eight-speed automatic is available for the Cadenza.

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 Cadenza doesn't offer an SMG or a conventional manual transmission.

For better stopping power the RLX Sport Hybrid's brake rotors are larger than those on the Cadenza:

The RLX stops shorter than the Cadenza:

The RLX's tires provide better handling because they have a lower 40 series profile (height to width ratio) that provides a stiffer sidewall than the Cadenza Premium's standard 45 series tires.

For better ride, handling and brake cooling the RLX has standard 19-inch wheels. Smaller 18-inch wheels are standard on the Cadenza Premium.

For better handling and stability, the track (width between the wheels) on the RLX is 1.1 inches wider in the front and .7 inches wider in the rear than the average track on the Cadenza.

The RLX handles at .84 G's, while the Cadenza Limited pulls only .79 G's of cornering force in a Motor Trend skidpad test.

The RLX executes Motor Trend's “Figure Eight” maneuver quicker than the Cadenza Limited (26.8 seconds @ .67 average G's vs. 27.6 seconds @ .63 average G's).

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

The RLX has 1.3 inches more front shoulder room, 1.6 inches more rear legroom and .5 inches more rear shoulder room than the Cadenza.

J.D. Power and Associates surveys of service recipients show that Acura service is better than Kia. J.D. Power ranks Acura 6th in service department satisfaction (above the industry average). With a 41% lower rating, Kia is ranked 20th.

The RLX Sport Hybrid has a standard remote vehicle starting system, so the vehicle can be started from inside the driver's house. This allows the driver to comfortably warm up the engine before going out to the vehicle. The climate system will also automatically heat or cool the interior. The Cadenza doesn't offer a remote starting system.

The RLX's power parking brake sets with one touch and releases with one touch or automatically. The Cadenza's parking brake has to released manually.

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

If the windows are left open on the RLX the driver can close them all at the outside door handle. On a hot day the driver can lower the windows at the outside door handle or from a distance using the keyless remote. The driver of the Cadenza can only operate the windows from inside the vehicle, with the ignition on.

The RLX's rain-sensitive wipers adjust their speed and turn on and off automatically based on the amount of rainfall on the windshield. This allows the driver to concentrate on driving without constantly adjusting the wipers. The Cadenza's standard manually variable intermittent wipers have to be constantly adjusted.

The RLX Sport Hybrid has standard automatic dimming rear and side view mirrors which automatically darken quickly when headlights shine on them, keeping following vehicles from blinding or distracting the driver. The Cadenza has an automatic rear view mirror, but its side mirrors don't dim.