Expert Reviews

2023 BMW M340i Review

AutoTrader SCORE
This score is awarded by our team of expert reviewers after extensive testing of the car
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With its 02 Series of the 1960s and ’70s and the 3 Series that followed, BMW was arguably the architect of the compact sport sedan.

It was a car that was loved not only by Yuppies, but also those who wanted the performance of a sports car with the comforts of a luxury sedan. These days BMW’s lineup is dominated by SUVs and an increasing number of electrified models – or at least its sales are. But lovers of sporty coupes and sedans can still find solace in a BMW dealership where models ranging from the 2 Series through the 8 Series, live up in varying degrees to the marque’s reputation for building drivers’ cars.

As the range continues to grow and evolve, the 2023 BMW M340i provides a pleasant reminder of just how refined and sophisticated the venerable 3 Series has become, and what a magnificent grand touring machine it is.

Styling: 9/10

The 3 Series isn’t draped in the sort of sheet metal that’ll make passersby crane their necks to catch a glimpse. It’s well-proportioned, dignified, and timelessly handsome, but it’s not revolutionary. The headlights, front- and rear aprons, and grille have been subtly updated for 2023, and while it is unmistakably a BMW from the front, the M340i has – at least to this point – avoided the giant bunny-tooth grille found on the M3.

As a bit of a ‘tweener model in the 3 Series lineup, the M340i wears sportier trim, a subtle deck-lid spoiler, and a notably aggressive-looking rear diffuser compared to the 330i. Where most grey paint options offered these days are as exciting as day-old oatmeal, the Skyscraper Grey Metallic finish on this test car is stunning in the way it reflects light in an almost liquid way.

The interior design generally subscribes to the same understated handsomeness as the exterior, but for 2023, last year’s double-hump displays – one for the digital gauges, the other for the central infotainment screen – have been replaced by a broad swath of glass housing a pair of larger displays. It’s a sign of the times, and while not beautiful, it’s at least mostly functional. Traditionalists – this author included – will continue to pine for the classic white-on-black dials from earlier Bimmers, but alas, those days are long gone.

The rest of the cockpit is reminiscent of last year’s 3 Series, which itself was an evolution of the past several generations, where clean, simple controls and trims are well-assembled and pleasing to the touch. There are some surfaces of black plastic that could benefit from fancying up, especially given the significant cost of this car, but all told it’s a great space to spend time behind the wheel.

Driving Feel: 9/10

Setting out from Los Angeles, the M340i proved to be the perfect partner for a high-speed freeway blast to Las Vegas. Around town and in traffic, it’s well-suited for commuting duties, offering just enough responsiveness through the steering, throttle, and braking to squirt through gaps while not feeling too twitchy or frenetic.

It’s at highway speeds that BMW’s Autobahn breeding comes to light, with the M340i able to swallow vast expanses of desert asphalt at speeds that can surprise the driver, making cruise control a useful tool for preserving one’s licence.

On the return trip to LA, the interstates were avoided in the interest of pursuing lesser-travelled secondary roads that featured plenty of whoops and random curves. Here, too, the BMW’s adaptive suspension kept the car composed yet comfortable, strafing across the desertscape.

It’s true the 3 Series has grown significantly over the generations, but it’s still got moves. Taking an identically-specced M340i around an autocross course last year showed off its quick, precise (if somewhat numb-feeling) steering, plus the reward of its combination of all-wheel drive, sticky summer tires, and taut suspension. The brakes provide serious stopping power when called upon, but more importantly, they offer great initial bite yet provide smooth, progressive pedal feel.

Power: 9.5/10

While the 3 Series has had four-, six-, and even eight-cylinder engines beneath its hood over the years, BMW’s celebrated inline six-cylinder has been one of its most endearing. Straight-sixes have helped define the 3 Series as a sport sedan over the years thanks to smooth, linear, free-revving power delivery.

The 2023 M340i carries on the tradition with a turbocharged 3.0L six-cylinder that gets an extra boost from a 48-volt mild-hybrid system nestled between the engine and the standard eight-speed automatic transmission. While providing greater operating efficiency, the real benefit of the hybrid is its kick of added responsiveness when the throttle is jabbed.

The M340i’s impressive 382 hp is appreciated, but it’s the 369 lb-ft of torque available from just off-idle speeds that provides gobs of thrust to generate the real excitement. It’s all backed by a delicious snarl and growling exhaust note, even if some of those sounds are enhanced by the audio system. Meanwhile, the eight-speed is smooth and unobtrusive most of the time, but it can snap off wickedly quick shifts in sport mode.

Fuel Economy: 7.5/10

For a sedan packing enough gusto to rip off a zero-to-100 km/h run in a very conservative 4.4 seconds, it’s decently efficient, too. Rated at 10.3 L/100 km in the city, 7.4 on the highway, and 9.0 combined, the M340i makes the most of the premium-grade gas it’s fed. The test car’s trip computer displayed a notable 32 mpg (7.4 L/100 km) average for the Vegas trip that featured highway driving speeds in excess of Canadian speed limits, and plenty of deep throttle dives on the back roads.

Comfort: 7.5/10

The suspension has been tuned for performance and tends more toward sportiness than suppleness. Even still, the adaptive drive settings can be set to take the edge off most bumps, and even in sport mode the ride isn’t as vicious as some of BMW’s sportiest machines from the past that prompted regular chiropractic visits.

BMW’s sport seats offer a lot of adjustability, including under-thigh support and side bolsters, but the leather in this tester seemed stretched extra tight over particularly stiff cushions, making them hard during long stints behind the wheel. Wind and road noise are very well suppressed, and engine noise only becomes notable when the driver calls for it in sport mode and with heavy throttle application.

Features: 7/10

As a luxury car, the finishes throughout generally speak to the M340i’s station in life, but in typical BMW fashion, most features are costly. There’s a large sunroof, onboard navigation, satellite radio, rain-sensing wipers, and wireless Apple CarPlay and Android Auto connectivity that worked fluidly during this test.

The test car also had heated (but not cooled) seats and a heated steering wheel, both of which were part of options packages in the U.S. but come standard in Canada. Shockingly, there was no adaptive cruise control, which is part of the Canadian-spec Driver Assistance package. The upgraded stereo is also an added-cost option, but its stellar sound quality makes it worth the added expense.

User Friendliness: 7/10

The shift to a larger screen panel swallows up some of the functions previously activated with physical buttons. The climate control and heated seat switches, for instance, are now touchpoints on the screen, and while this move is usually lamented, it works well enough here. The screen is responsive, and with the climate control set to automatic the occasional tap for a slight increase or decrease in temperature is really all that’s needed. Hard buttons remain for defrost and the audio system’s volume control.

BMW’s eighth generation iDrive is found here and it’s a slick, effective way of handling a lot of inputs through either touchscreen or rotary-knob controller input. The latter also has a touchpad on top to enable finger-drawing for characters and numbers, and BMW’s voice command system works well, too.

Another change for 2023 is the replacement of the shift lever on the centre console with a smaller toggle switch for reverse, neutral, and drive, and a separate button for park. While it seems like the answer to a question nobody asked, it works logically and easily.

Practicality: 7/10

The 3 Series offers seating places for five occupants, although the centre rear passenger will not only be crowded for shoulder space but also have to sit with their legs splayed around the driveshaft tunnel. It’s decently spacious for four people, however, with more rear seat leg- and headroom than competitors like the Lexus IS and Genesis G70. At 481 L, the trunk offers more space than its competitors and the ability to fold the split rear seat adds to its practicality.

Safety: 9/10

The BMW M340i is a safe car, too. The United States National Highway Traffic Safety Administration (NHTSA) has awarded the 2023 3 Series its top five-star rating, and while the Insurance Institute for Highway Safety (IIHS) hadn’t tested the 2023 model at the time of this writing, the 2022 received a Top Safety Pick rating.

BMW offers plenty of passive and active safety features on the M340i, however, many of them are bundled into sometimes confusing option packages. Fortunately, BMW Canada offers fewer – if costlier packages – that are more inclusive. For the full gamut of driver assistance, the $2,000 Advanced Driver Assistance pack should do the trick.

Value: 7/10

BMW’s 3 Series has never been a cheap car, but with careful option selections, it can be a decent value. The M340i is capable of very impressive performance, with power that would’ve eclipsed the vaunted M3 from even a few years ago, but as its size and technology has increased, and so has its sticker price. A similarly specced Canadian car to this American tester rings in at $78,345 before freight and taxes.

The Verdict

More than one million units of the current generation 3 Series have been sold globally, making this the most successful generation yet – and that’s in spite of a growing love for SUVs. And while BMW’s small sport sedan is not so small anymore, it still offers a masterful blend of style, performance, and luxury that’s made it such a popular choice for nearly 50 years.

The 2023 BMW M340i gets subtle but effective styling updates, and aligns the cockpit design with other contemporary BMW models that are dominated by the large glass panel dashboard. Whether this is actually an improvement or annoyance will be up to individual customer tastes, but there’s no question BMW’s class-defining sport sedan remains a competent and rewarding driving experience, and a brilliant grand tourer.

Engine Displacement 3.0L
Engine Cylinders Turbo I6
Peak Horsepower 389 hp @ 5,000 rpm
Peak Torque 369 lb-ft @ 1,600 rpm
Fuel Economy 10.3 / 7.4 / 9.0 L/100 km cty/hwy/cmb
Cargo Space 481 L
Model Tested 2023 BMW M340i xDrive
Base Price $66,000
A/C Tax $100
Destination Fee $2,480
Price as Tested $80,925
Optional Equipment
$12,345 – Tacora Red leather, $1,900; Skyscraper Grey Metallic paint, $895; BMW M 50 Years emblems, $300; Aluminum Fabric Trim, $500; Wireless Charging, $350; Advanced Driver Assistance Package (Canadian spec), $2,000; M Sport Pro Package, $1,500; Premium Enhanced Package, $4,900