2023 BMW M340i Review: The Quintessential Sports Sedan

BMWs have long been renowned for their driving dynamics and performance pedigree, particularly within the iconic 3 Series lineup. The M340i sits just below the full-blown M3, promising an exciting blend of power, agility, and everyday practicality. But in a world where performance sedans face stiff competition, does the M340i still deliver that quintessential BMW experience?

The short answer is yes, the 2023 BMW M340i is arguably the best balanced and most compelling performance variant of the current 3 Series range, delivering thrilling acceleration, composed handling, and a surprising level of comfort when needed.

A Potent Powerplant

Right off the bat, the heart of the M340i is its stellar BMW B58 3.0-liter turbocharged inline-six engine. This silky-smooth powerplant churns out an impressive 382 horsepower and 369 lb-ft of torque, rocketing the sedan from 0-60 mph in just 4.1 seconds with xDrive all-wheel-drive. The inline-six configuration, a hallmark of BMW’s heritage, delivers power in a beautifully linear fashion that’ll keep you grinning from stoplight to stoplight.

To enhance efficiency, BMW has incorporated a 48-volt mild-hybrid system, providing a smidge of electric boost while allowing for extended engine auto-start/stop operation. This helps the M340i achieve a combined 26 mpg – impressive for a car with this level of performance.

Quick-Revving Inline-Six with a Delightful Growl

As Car and Driver notes, the B58 engine is “turbine smooth with a healthy growl.” While not quite as aurally thrilling as BMW’s previous naturally-aspirated inline-sixes, the M340i still rewards with a “whirry straight-six noise complete with subtle burbles in Sport Plus mode,” according to The Drive’s review.

Power routes through an excellent ZF 8-speed automatic transmission that fires off rapid, crisp shifts whether left in automatic mode or using the steering wheel-mounted paddle shifters. The only demerit is the lack of a true manual transmission option.

Balanced Driving Dynamics

Under the skin, the M340i is based on BMW’s excellent CLAR platform that underpins the entire 3 Series range. However, the M Performance model benefits from several hardware upgrades over “standard” variants:

• M Sport Brakes: Larger vented discs (13.7-inch front, 13.6-inch rear) provide reassuring stopping power.
• M Sport Differential: An electronically-controlled rear limited-slip differential helps maximize traction when powering out of corners.
• M Sport Suspension: The adaptive dampers can switch between a comfortable, planted setup for daily driving or a firmly controlled attitude for backroad blasts.

With the right options ticked, the M340i can be a serious performance machine or a composed luxury cruiser at the push of a button.

Supreme Agility and Poise

Out on the open road, the M340i simply shines. The steering is accurate and well-weighted, even if it doesn’t quite match BMW’s hydraulic racks of old for outright communication. Body control is exemplary, and the M340i carves through corners with minimal body roll and excellent front-end bite.

Evo Magazine’s review highlights the M340i’s impressive chassis capability, stating it “manages to find breadth and control even through the most brutal dips and undulations.” The advanced xDrive all-wheel-drive system provides tenacious grip, allowing the sedan to simply hunker down and fire out of corners.

For driving purists, the xDrive’s rear bias and the rear limited-slip differential enable a delightful dose of back-end mobility when pushed. Disable stability control completely, and the M340i will easily oversteer and hang its tail out in proper BMW fashion. It’s an absolute hoot on a twisting backroad.

Yet when driven sedately, the M340i maintains a startlingly comfortable and refined demeanor. The adaptive dampers soak up bumps admirably, and road/wind noise is well-subdued, making it easy to simply waft along in luxury.

A Premium, Tech-Laden Interior

Slide inside the M340i’s cabin, and you’re treated to an upscale, driver-focused environment that masterfully blends modern tech with traditional BMW design cues.

The standard SensaTec upholstery looks and feels far richer than typical leatherette, while genuine leather, heated seats, and a heated steering wheel are available upgrades. The supportive sport seats keep occupants planted during spirited driving stints, yet they’re all-day comfortable for highway road trips.

At the center of the experience is BMW’s slick curved display, consisting of a 12.3-inch digital instrument cluster and a 14.9-inch infotainment touchscreen. The latest iDrive 8 software is snappy and intuitive, combining touchscreen, voice controls, and the usual BMW click-wheel on the center console.

While impressive, this tech-forward layout does come with some quirks. Car and Driver laments the lack of hard buttons for climate controls, with these functions now absorbed into the touchscreen menus. Some may also miss the traditional gear lever, replaced by a compact toggle switch.

Other interior highlights include wireless Apple CarPlay/Android Auto, a thumping Harman/Kardon audio system, and the latest BMW safety/driver assistance features. Those seeking more exclusivity can opt for BMW Individual customization or the ultra-luxurious Swedesn Yacht Designer Collection.

With a generous 16.9 cubic feet trunk and folding rear seatbacks, the M340i also serves as a reasonably practical daily driver, even if rear seat room isn’t limo-like.

How It Stacks Up Against Key Rivals

In the compact luxury sport sedan arena, the BMW M340i faces some stiff competition from the likes of:

• Audi S4: Although down on power with its 349 hp turbocharged V6, the S4 delivers precise handling, a more buttoned-down demeanor, and arguably leads the pack in interior tech/design. Pricing starts around $56,000.
• Genesis G70 3.3T: The dark horse in this segment, the Genesis packs a potent 365 hp twin-turbo V6 and outstanding value (around $43,000 to start), even if it can’t quite match the BMW’s overall polish and driving dynamics.
• Mercedes-AMG C43: The facelifted 2023 C43 ditches its previous V6 in favor of an electrified 2.0L turbo-four making 402 hp – quick in a straight line but lacking the refined character of the BMW’s inline-six. Pricing is steep at over $63,000.

The Tesla Model 3 Performance stands as an intriguing all-electric alternative, capable of dusting the M340i’s straight-line performance. However, it simply can’t match the BMW’s overall driving engagement and interior ambiance, though it does pack an ultra-modern all-electric cabin.

For those able to stretch their budget into the $70,000+ range, the BMW M3 makes a compelling case with its 473 hp twin-turbo inline-six, motorsport-derived chassis, and even sharper handling response. But you’ll sacrifice some daily compliance and practicality in exchange for that increased performance potential.

The 2023 BMW M340i: The Goldilocks Pick

For most driving enthusiasts seeking a premium compact sport sedan, the 2023 BMW M340i makes a incredibly strong case as the “just right” pick in the current 3 Series lineup. It delivers scorching straight-line performance courtesy of its rip-snorting turbo inline-six, yet it can also transform into a comfortable long-distance cruiser at the flip of a drive mode switch.

The M340i embraces BMW’s enthusiast roots with its composed rear-biased chassis, accurate steering, and eagerness to hang its tail out when pushed. Yet it packages all that driving verve into a reasonably practical four-door sedan with a well-appointed interior laden with tech and luxury features.

Admittedly, the M340i can’t quite match the razor-sharp response and outright performance potential of the full-fat M3 Competition model. Those seeking the ultimate track toy may want to stretch their budget for that vehicle. But in the real world of driving on back roads and highways, the M340i offers a sublime blend of performance and livability that few rivals can match.

Pricing is extremely competitive too. With an MSRP starting under $60,000 for rear-wheel-drive variants, the M340i drastically undercuts the latest Mercedes-AMG C43 and even the Audi S4 in some cases. Allied with BMW’s strong residual values, it makes a compelling value proposition within this premium performance space.

For buyers able to indulge, there’s also a dizzying array of optional packages and design elements to craft a truly bespoke M340i. From the ultra-luxurious Swedish yacht-inspired cabin trims to the wild Portimao Blue Metallic exterior paint, BMW allows enthusiasts to tailor this sport sedan to their exact tastes.

The Bottom Lines                                                

The 2023 BMW M340i carves out a sweet spot as the most compelling and well-rounded performance variant in the latest 3 Series range. With a potent yet refined turbocharged inline-six, cutting-edge tech amenities, and impeccable driving dynamics, it embodies the best attributes of BMW’s legendary sport sedans while avoiding the compromises of the full M3.

For driving enthusiasts who want thrilling performance without sacrificing day-to-day livability, the M340i simply nails the brief. It’s the perfect balance of power, luxury, and agility that remains true to BMW’s roots. While alternatives from Mercedes, Audi, and Genesis merit consideration, few can match the wholistic appeal and fan-favorite status of this Goldilocks-zone 3 Series.