Compare the2024 Lexus ISVS 2023 Infiniti Q50

For enhanced safety, the front and rear seat shoulder belts of the Lexus IS have pretensioners to tighten the seatbelts and eliminate dangerous slack in the event of a collision and force limiters to limit the pressure the belts will exert on the passengers. The Infiniti Q50 doesn’t offer pretensioners for its rear seat belts.

The Lexus IS has standard driver and front passenger side knee airbags mounted low on the dashboard. These airbags helps prevent the driver and front passenger from sliding under their seatbelts or the main frontal airbags; this keeps them better positioned during a collision for maximum protection. Knee airbags also help keep the legs from striking the dashboard, preventing knee and leg injuries in the case of a serious frontal collision. The Q50 doesn’t offer knee airbags.

The IS has a standard Secondary Collision Brake, which automatically applies the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The Q50 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.

Both the IS and the Q50 have standard driver and passenger frontal airbags, front side-impact airbags, side-impact head airbags, height adjustable front shoulder belts, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, lane departure warning systems, blind spot warning systems, rearview cameras, rear cross-path warning, available all wheel drive and around view monitors.

For its top level performance in IIHS driver and passenger-side small overlap frontal, moderate overlap frontal, side impact, roof strength and head restraint tests, its standard vehicle-to-vehicle front crash prevention system, its standard vehicle-to-pedestrian front crash prevention system, and its standard headlight’s “Good” rating, the Insurance Institute for Highway Safety grants the IS its highest rating: “Top Safety Pick Plus” for 2022, a rating granted to only 126 vehicles tested by the IIHS. The Q50 is not even a standard “Top Safety Pick.”

There are over 20 percent more Lexus dealers than there are Infiniti dealers, which makes it easier should you ever need service under the IS’ warranty.

J.D. Power and Associates rated the IS first among compact premium cars in their 2023 Initial Quality Study. The Q50 isn’t in the top three.

J.D. Power and Associates’ 2023 Initial Quality Study of new car owners surveyed provide the statistics that show that Lexus vehicles are better in initial quality than Infiniti vehicles. J.D. Power ranks Lexus above average in initial quality. With 41 more problems per 100 vehicles, Infiniti is rated below average.

J.D. Power and Associates’ 2022 survey of the owners of three-year-old vehicles provides the long-term dependability statistics that show that Lexus vehicles are more reliable than Infiniti vehicles. J.D. Power ranks Lexus above average in long-term dependability. With 33 more problems per 100 vehicles in the first three years of ownership, Infiniti is rated below average.

The IS 500’s 5.0 DOHC V8 produces 72 more horsepower (472 vs. 400) and 45 lbs.-ft. more torque (395 vs. 350) than the Q50 Red Sport 400’s optional 3.0 turbo V6.

As tested in Car and Driver the IS 500 5.0 DOHC V8 is faster than the Q50 Red Sport 400:

On the EPA test cycle the IS gets better mileage than the Q50:

In its Green Vehicle Guide, the U.S. Environmental Protection Agency (EPA) rates the Lexus IS higher (5 out of 10) than the Infiniti Q50 (3). This means the IS produces up to 16.5 pounds less smog-producing pollutants than the Q50 every 15,000 miles.

An eight-speed automatic is standard on the Lexus IS, for better acceleration and lower engine speed on the highway. Only a seven-speed automatic is available for the Q50.

For better stopping power the IS’ front brake rotors are larger than those on the Q50:

The IS stops shorter than the Q50:

For better traction, the IS has larger standard tires than the Q50 (235/45R18 vs. 225/50R18).

The IS 300’s standard tires provide better handling because they have a lower 45 series profile (height to width ratio) that provides a stiffer sidewall than the Q50 Luxe’s standard 50 series tires.

The IS has a standard space-saver spare tire so you can replace a flat tire and drive to have the flat repaired or replaced. A spare tire isn’t available on the Q50; it requires you to depend on its run-flat tires, which limits mileage and speed before they are repaired. If a run-flat is damaged beyond repair by a road hazard your vehicle will have to be towed.

The IS 500 F Sport’s has front and rear gas-charged shocks for better control over choppy roads. The Q50 Red Sport 400’s suspension doesn’t offer front gas-charged shocks.

For better handling and stability, the average track (width between the wheels) on the IS is 1.7 inches wider in the front and 1.1 inches wider in the rear than the average track on the Q50.

The IS 500 Performance handles at .89 G’s, while the Q50 Red Sport 400 pulls only .88 G’s of cornering force in a Car and Driver skidpad test.

For better maneuverability, the IS’ turning circle is 2.5 feet tighter than the Q50’s (34.2 feet vs. 36.7 feet). The IS AWD’s turning circle is 2 feet tighter than the Q50 AWD’s (35.4 feet vs. 37.4 feet).

The IS is 4.2 inches shorter than the Q50, making the IS easier to handle, maneuver and park in tight spaces.

The IS has .3 inches more front legroom, 1.1 inches more front hip room, .1 inches more rear headroom and 1.5 inches more rear hip room than the Q50.

The IS has a maintenance free battery for long life without checking the battery’s water level. The Q50 doesn’t have a maintenance free battery, so the water level in the battery’s cells must be checked often to prevent damage.

J.D. Power and Associates surveys of service recipients show that Lexus service is better than Infiniti. J.D. Power ranks Lexus first in service department satisfaction. With a 35% lower rating, Infiniti is ranked 9th.

Unlike the driver-only memory system in the Q50, the IS offers an optional driver and passenger memory, so that when drivers switch, the memory setting adjusts the driver’s seat, steering wheel position and outside mirror angle and the front passenger seat also adjusts to the new passenger’s preset preferences.

The IS’ 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 Q50 does not have an oil pressure gauge.

The IS’ power parking brake sets with one touch and releases with one touch or automatically. The Q50’s parking brake has to be released manually.

Consumer Reports rated the IS’ headlight performance “Very Good,” a higher rating than the Q50’s headlights, which were rated “Good.”

The Insurance Institute for Highway Safety (IIHS) conducts detailed tests on headlights for their range both straight ahead and in curves and to be certain they don’t exceed acceptable amounts of glare to oncoming drivers. The IS’ headlights were rated “Good” to “Acceptable” by the IIHS, while the Q50’s headlights are rated “Marginal.”

A power rear sunshade is optional in the IS to help block heat and glare for the rear passengers. The Q50 doesn’t offer a rear sunshade.

Optional air-conditioned seats in the IS keep the driver and front passenger comfortable and take the sting out of hot seats in Summer. The Q50 doesn’t offer air-conditioned seats.

According to The Car Book by Jack Gillis, the IS is less expensive to operate than the Q50 because it costs $127 less to do the manufacturer’s suggested maintenance for 50,000 miles. Typical repairs cost less on the IS than the Q50, including $174 less for a muffler, $14 less for front brake pads, $44 less for a fuel pump and $196 less for front struts.

Consumer Reports® recommends both the Lexus IS and the Infiniti Q50, based on reliability, safety and performance.

J.D. Power and Associates rated the IS first among compact premium cars in owner reported satisfaction. This includes how well the vehicle performs and satisfies its owner’s expectations. The Q50 isn’t in the top three.

The Lexus IS outsold the Infiniti Q50 by over four to one during 2022.