Tested: 2023 BMW M340i xDrive Keeps Things Fresh

Sedans are a dying breed in America. Last year, cars of all kinds comprised only 21 percent of sales. That doesn’t bode well for one of our favorite vehicles—the sports sedan. Even at BMW, home of the sports sedan, cars represented just 34 percent of sales in 2022. Ten years earlier, they were 30 percentage points higher. And the 3-series, the car that we have long regarded as the core of the BMW brand, hasn’t been the sales leader since 2018. Either the X3 or the X5—or both of them—has outsold these compacts, even combined with the 4-series.

So it’s gratifying to see that BMW is still making a strong effort to keep these models up-to-date and competitive. For 2023, the 3-series, four years into its latest generation, has received its Life Cycle Impulse (LCI)—BMW-speak for a mid-cycle refresh.

The LCI models carry subtle aesthetic differences. The headlights are slimmer and simpler, with twin, inverted L-shaped daytime running lights in each light. The lower air intake appears larger due to a blacked-out upper portion, and the corner air inlets are simpler and clear. Mercifully, the 3-series has been spared the vertical-nostril look. The rear bumpers are now more sculpted, and the black exterior trim is now standard. The M340i also gets trapezoidal tailpipes and a standard, subtle rear spoiler. Overall, the new model retains excellent proportions and looks good.

Inside, the most obvious change is BMW’s Curved Display, which houses a 12.3-inch screen for the instrument cluster and a 14.9-inch touchscreen for the iDrive 8 infotainment system, the latest version on offer. That screen is a lot larger than the 10.3-inch one in the earlier 3-series, but it comes with a price.

Instead of a long strip of physical switches, the 13 HVAC buttons below the center register are now gone, as are the audio controls and radio presets. Now there’s just a single strip comprising two audio and two defroster buttons—and a welcomed volume knob. Turning on your seat heater requires a couple of actions to get to the right screen, or a voice command—either of which is slower and more cumbersome than simply pressing a hard switch.

Another big change is the loss of the gear lever, replaced by a recessed toggle. Both mechanisms work in similar fashions in electronically controlled transmissions, but there’s definitely something more aesthetically satisfying about a proper lever, especially since there seems to be no storage or cupholder benefit from the toggle design. At least there are two well-positioned steering-wheel paddles for manual shifting.

The eight-speed automatic transmission controlled by this shifter remains the excellent ZF 8HP, enhanced by the 48-volt hybrid system that’s spreading through the BMW lineup. A starter-generator connected to the engine’s crankshaft and residing in the transmission housing provides as much as 147 pound-feet of torque but only about 13 horsepower to supplement the combustion engine. Electrical power comes from a small 48-volt battery under the trunk floor, where the previous 12-volt battery was mounted.

This electrified gearbox shifts intelligently and seamlessly and seems to summon the perfect gear for every driving condition. The transmission offers three different shift schedules matching the car’s Comfort, Sport, and Sport+ modes, as well as full manual control using the paddles. As we prefer, the transmission does not upshift at redline when in manual mode.

The transmission’s job is made easier by being coupled with BMW’s superb B58 turbocharged 3.0-liter inline-six. Despite the new hybrid components, peak power and torque—382 horsepower at 5800 to 6500 rpm and 369 pound-feet of torque between 1800 and 5000 revs—are unchanged from earlier nonhybrid iterations. That thrust is delivered very smoothly and without a discordant note.

The performance of our all-wheel-drive test car is similar to that of the earlier rear-drive cars we’ve tested. With additional traction, the xDrive model launches harder and hits 60 mph in 3.7 seconds, a tenth quicker than our long-term, rear-drive M340i. And it covers the quarter-mile in 12.2 seconds at 112 mph, a tenth quicker but 3 mph slower than before. As speeds increase, this M340i’s acceleration deficit increases thanks to the extra 160 pounds imposed by the all-wheel drive and hybrid-system hardware. By 130 mph, which arrives in 17.0 seconds flat, the xDrive is about a second in arrears of its rear-drive sibling. Still, this car easily keeps up with a Cadillac CT4-V Blackwing.

In normal driving, this M340i feels very quick and effortlessly muscular. The combination of the turbocharged engine, the excellent transmission, and the hybrid system provides seamless power. Turbo lag is essentially nonexistent unless you floor the throttle from a dead stop. Under that circumstance, you’ll wait a good second before the powertrain musters full thrust. Fortunately, there’s enough motive force, even off boost, that you don’t notice this in most driving.

Our lead feet only averaged 19 mpg in the Bimmer, but our 75-mph highway average was an excellent 33 mpg. We suspect that most owners will get mileage into the mid-20s, which aligns with EPA estimates for combined city and highway driving. It doesn’t hurt that this generation of 3-series has a drag coefficient of 0.27 and isn’t punching an SUV-sized hole in the atmosphere.

Unfortunately, the M340i’s chassis doesn’t quite measure up to its powertrain. The peak capabilities are excellent, with 0.95 g of cornering grip and a stopping distance of 155 feet from 70 mph. But the steering has a poor sense of on-center and an inconsistent effort during cornering, perhaps attributed to the variable-ratio steering rack that’s standard on all 340s. Brake feel isn’t much better, with deceleration being more proportional to pedal travel than pedal effort.

That said, you can cover ground very rapidly on winding roads. The steering might not feel great, but it’s accurate, the brakes are powerful and fade-free, and body control is good, even with the suspension in Comfort mode.

Of course, the point of a sports sedan is to provide joy in the mountains and also be practical for workaday tasks. In that role, the M340i imposes a few penalties. Even in Comfort, the suspension is surprisingly stiff and jiggly, and Sport is way too much for regular use. High tire pressures play a part here, with the summer tires asking for 44 psi for speeds over 100 mph. Airing down to 39 psi for under 100 mph marginally improves the ride.

Though we measured a 70-mph sound level of only 68 dBA, our car sounded louder than that. Otherwise, it was very comfortable with excellent seats and decent interior space, though interior volume is not much different than the older E90-generation 3-series, despite a body some seven inches longer. It will hold four average-size adults, if the ones in the rear don’t want to cross their legs. All we’d ask is a steering column that could adjust about an inch lower than it currently does.

Overall, it’s hard to argue with the BMW M340i’s objective performance. It’s extremely quick, pretty comfortable, and it easily devours challenging mountain roads. But it is perhaps too eager to embrace the half-baked future. We’d happily trade its ambient light show for an instrument cluster with round gauges and enough dimming so that it doesn’t glare on an empty country road. We’d exchange the toggle for a genuine shift lever, preferably controlling a modern manual transmission—even if it cost a few mpg. More buttons on the dashboard and fewer icons on the display might encourage us to concentrate on our driving more than our electronics.

But in an age when the future promises a sea of electric-powered SUVs, we are grateful for still having such a powerful and capable sports sedan. Even with a few flaws.

Contributing Editor

Csaba Csere joined Car and Driver in 1980 and never really left. After serving as Technical Editor and Director, he was Editor-in-Chief from 1993 until his retirement from active duty in 2008. He continues to dabble in automotive journalism and LeMons racing, as well as ministering to his 1965 Jaguar E-type, 2017 Porsche 911, and trio of motorcycles—when not skiing or hiking near his home in Colorado.