BMW's cheapest performance car now has Audi RS3 power for £13,000 less
Munich’s popular 3-litre straight-six has been given an update for 2026, making BMW’s M-lite range even more competitive than before
The 3-litre twin-turbocharged B58 straight-six is often considered the modern 2JZ thanks to its tuning headroom, but now BMW has given it some of its own upgrades. Announced as part of an overall update to the lineup for 2026, an increase in performance, reduction in emissions and various changes to trim across the range are all set to come into effect before the end of the year.
For 2026, BMW is increasing output of three popular models equipped with the mild-hybrid B58 straight-six, spanning from the ‘entry-level M’ M240i xDrive, through to the M340i (saloon and estate) and all three iterations of the M440i. The power increase sees the unit go from 369bhp and 368lb ft of torque to 387bhp and 398lb ft, increases of 18bhp and 30lb ft.
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While the new output numbers are consistent between all three of the aforementioned models, performance figures are not. BMW says some models like the M340i xDrive saloon now hit 62mph from a standstill a tenth quicker than before, bringing its sprint down to 4.3sec, but the M240i xDrive is no quicker than before with its 0-62mph at the same 4.3sec.
What has improved for the M240i is efficiency, with its fuel economy said to have gone from under 27mpg to just shy of 30mpg on the WLTP cycle. This has been achieved by switching from a belt to crankshaft starter generator system, reducing losses in the 48V hybrid assist and improving refinement of the start/stop function in the process. Like the other models, emissions have also been reduced in-line with regulations, with the M240i going from 200g/km to 183g/km, 20 per cent less than the current S58-powered G80 M3 and over 100g/km less than the naturally aspirated V8 E9X M3, a car with not far from the same power output…
These minor tweaks have quietly made these ‘M-lite’ models some of the most potent offerings for the money, with the M240i still under the £50,000 mark despite its near-400bhp output. Stack it head-to-head with the Audi RS3 and things don’t look so good for Ingolstadt on-paper, with the nearly identically powerful five-cylinder hatch costing almost £13,000 more than the BMW.
Elsewhere in BMW’s lineup, it’s adding new colours to the 2-series Gran Coupe, interior tweaks to the X3 SUV and making those trick rear ‘laser lights’ standard on the i4 and 4-series Gran Coupe should you option the Adaptive LED headlights – this will also become an individual option on more entry-level models such as the 420i and 420d, without paying for the pricey M Sport Pro package. And hold the front page… the 5-series range will also now get a coat hook on the B-pillar.
BMW will roll these changes out to cars produced from November and December, with cars hitting the road in the UK thereafter.
