2019 Hyundai Ioniq Plug-In Hybrid vs. 2018 Mercedes C 350e

Detailed Review, Specifications & Comparison

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To help make backing safer, the Ioniq Plug-In Hybrid’s optional cross-path warning system uses wide-angle radar in the rear bumper to alert the driver to vehicles approaching from the side, helping the driver avoid collisions. The C 350e doesn’t offer a cross-path warning system.

Both the Ioniq Plug-In Hybrid and the C 350e have standard driver and passenger frontal airbags, front side-impact airbags, driver knee airbags, side-impact head airbags, front seatbelt pretensioners, height adjustable front shoulder belts, plastic fuel tanks, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, daytime running lights, rearview cameras, available crash mitigating brakes, lane departure warning systems, blind spot warning systems, rear parking sensors and driver alert monitors.


The Ioniq Plug-In Hybrid comes with a full 5-year/60,000-mile basic warranty, which covers the entire car and includes 24-hour roadside assistance. The C 350e’s 4-year/50,000-mile basic warranty expires 1 year and 10,000 miles sooner.

Hyundai’s powertrain warranty covers the Ioniq Plug-In Hybrid 6 years and 50,000 miles longer than Mercedes covers the C 350e. Any repair needed on the engine, transmission, axles, joints or driveshafts is fully covered for 10 years or 100,000 miles. Coverage on the C 350e ends after only 4 years or 50,000 miles.

The Ioniq Plug-In Hybrid’s corrosion warranty is 2 years longer than the C 350e’s (7 vs. 5 years).

There are over 2 times as many Hyundai dealers as there are Mercedes dealers, which makes it much easier should you ever need service under the Ioniq Plug-In Hybrid’s warranty.


J.D. Power and Associates’ 2018 Initial Quality Study of new car owners surveyed provide the statistics that show that Hyundai vehicles are better in initial quality than Mercedes vehicles. J.D. Power ranks Hyundai third in initial quality, above the industry average. With 18 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 Hyundai vehicles are more reliable than Mercedes vehicles. J.D. Power ranks Hyundai 6th in reliability, above the industry average. With 23 more problems per 100 vehicles, Mercedes is ranked 15th.

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

Fuel Economy and Range

On the EPA test cycle the Ioniq Plug-In Hybrid gets better fuel mileage than the C 350e:




C 350e



Running on Electricity

123 city/114 hwy

45 city/61 hwy



Running on Gasoline

53 city/52 hwy

28 city/32 hwy


The Ioniq Plug-In Hybrid’s maximum driving range in pure electric mode is 27 miles, three times as far as the C 350e’s 9 mile range.

To lower fuel costs and make buying fuel easier, the Hyundai Ioniq Plug-In Hybrid uses regular unleaded gasoline. The C 350e requires premium, which can cost 20 to 55 cents more per gallon.


The Ioniq Plug-In Hybrid 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 C 350e doesn’t offer an SMG or a conventional manual transmission.

Suspension and Handling

For better handling and stability, the track (width between the wheels) on the Ioniq Plug-In Hybrid is 1.3 inches wider in the rear than on the C 350e.

For better maneuverability, the Ioniq Plug-In Hybrid’s turning circle is 2 feet tighter than the C 350e’s (34.78 feet vs. 36.8 feet).


The Hyundai Ioniq Plug-In Hybrid may be more efficient, handle and accelerate better because it weighs about 600 pounds less than the Mercedes C 350e.

The Ioniq Plug-In Hybrid is 8.5 inches shorter than the C 350e, making the Ioniq Plug-In Hybrid easier to handle, maneuver and park in tight spaces.

The design of the Hyundai Ioniq Plug-In Hybrid amounts to more than styling. The Ioniq Plug-In Hybrid has an aerodynamic coefficient of drag of .24 Cd. That is significantly lower than the C 350e (.28) and many sports cars. A more efficient exterior helps keep the interior quieter and helps the Ioniq Plug-In Hybrid get better fuel mileage.

The front grille of the Ioniq Plug-In Hybrid uses electronically controlled shutters to close off airflow and reduce drag when less engine cooling is needed. This helps improve highway fuel economy. The C 350e doesn’t offer active grille shutters.

Passenger Space

Because it has more passenger and cargo room, the EPA rates the Ioniq Plug-In Hybrid a Mid-size car, while the C 350e is rated a Compact.

The Ioniq Plug-In Hybrid has 6.2 cubic feet more passenger volume than the C 350e (96.2 vs. 90).

The Ioniq Plug-In Hybrid has 2 inches more front headroom, .5 inches more front legroom, .8 inches more front shoulder room, .3 inches more rear headroom and .5 inches more rear legroom than the C 350e.

Cargo Capacity

The Ioniq Plug-In Hybrid has a much larger trunk than the C 350e (23 vs. 11.8 cubic feet).


To shield the driver and front passenger’s vision over a larger portion of the windshield and side windows, the Ioniq Plug-In Hybrid has standard extendable sun visors. The C 350e doesn’t offer extendable visors.

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

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