New BMW 3 Series prototype review: a thrilling exec for the modern era

Verdict

BMW has dragged a classic into the modern era with great effect. The upcoming 3 Series boasts an even broader breadth of ability, blending daily comfort and weekend thrills, plus strong safety, sharp handling, and cutting-edge connectivity.

The eighth-generation BMW 3 Series is already shaping up to be a winner. The maker has been building the model since 1975, cementing its reputation over five decades as the definitive all-round sporty mid-sized saloon. 

Come autumn 2026, the eighth generation will be ready to hit the roads. This new model acts as a combustion-engined sibling to the upcoming 'Neue Klasse' EVs, boasting exceptional connectivity and lightning-fast driving dynamics. We’ll be driving both within the next couple of months, but to see what’s in store, BMW has thrown us the keys to a camouflaged, near-production M350 xDrive prototype to see what it’s made of.

Thanks to its roots in the Neue Klasse architecture, the G50 is closely related to the electric i3 and iX3 models. From these electric siblings, the new 3 Series inherits a highly advanced digital brain, meaning every future 3 Series will feature the brand’s innovative 'Panoramic iDrive' infotainment set-up, BMW Operating System X, AI-integrated voice control, and ultra-fast communication between the powertrain, chassis and stability control systems.

Used - available now

2014 BMW

3 Series

86,000 milesAutomaticDiesel3.0L

Cash £9,995

View 3 Series

2018 BMW

3 Series

49,200 milesAutomaticDiesel2.0L

Cash £15,495

View 3 Series

2024 BMW

3 Series

76,426 milesAutomaticDiesel2.0L

Cash £22,338

View 3 Series

2022 BMW

3 Series

81,718 milesAutomaticPetrol2.0L

Cash £15,792

View 3 Series

However, this shared technology doesn't apply to the metal underpinnings. While the electric i3 uses its floorpan to house battery packs, the combustion-engined 3 Series leaves plenty of room beneath the floor. Consequently, the seat brackets are mounted significantly lower, with a traditional exhaust system and propshaft running directly between them.

The new 3 Series family, internally codenamed G50, will feature four and six-cylinder engines. Every model will be equipped with a 48-volt mild-hybrid system, ensuring they are both powerful and efficient. At the top of the tree sits the 437bhp M350 xDrive – the car we’re driving here.

The M350 – note BMW is dropping the ‘i’ from its combustion cars, to help separate them from its electric cars – comes with an eight-speed automatic gearbox and a specially tuned four-wheel-drive system. Alongside millisecond-fast, variable power distribution, drivers can select a pure rear-wheel-drive mode at the touch of a button. 

14

If buyers opt for the most comprehensive ‘M’ package, the driving experience is further enhanced by variable-ratio steering, large 20-inch alloy wheels with mixed tyres (245/35 R20 at the front and 275/30 R20 at the rear), uprated brakes, adaptive dampers and heavily bolstered front seats.

BMW has worked tirelessly to widen the new car's bandwidth between everyday usability and outright driving enjoyment. Upgrades include thicker anti-roll bars, a longer wheelbase, a wider track, increased caster, stiffer wishbone mounts and a highly balanced weight distribution. 

The result is thrilling. The 3 Series feels incredibly versatile, acting as a relaxed cruiser with excellent ride comfort and supple steel springs, yet with the ability to transform instantly into an agile, engaging sports saloon with a genuine connection to the road. The steering is exceptionally precise, self-centring cleanly without demanding too much effort, and perfectly weighted for all speeds. It turns in sharply and feels tightly controlled without any harsh, jarring stiffness.

The refined and punchy engine perfectly matches this character. The turbocharged 3.0-litre straight-six delivers a hefty 580Nm of torque, and while the engine block is familiar from other BMWs, it feels particularly alert and gritty here. 

A mild-hybrid electric motor seamlessly bridges the gap before the turbocharger fully spools, sending an extra 40Nm of force directly to the gearbox. Using the cleverly animated launch control, the M350 sprints off the line perfectly. 

Without any torque-converter slip or rear-end twitchiness, the 1.8-tonne saloon fires through its gears, completing the 0-62mph dash in just 4.1 seconds and feeling as controlled as a much lighter sports car. On this evidence, the 3 Series looks certain to retain its crown as the best-driving mid-size saloon on sale.

Did you know you can sell your car through Auto Express? We’ll help you get a great price and find a great deal on a new car, too.