BMW Z4 M40i review – 2024 roadster is still no Porsche beater

The G29-generation BMW Z4 hasn’t set the world alight since its launch in 2018, either in terms of sales or reputation as a sports car for keen drivers. In terms of usability, comfort and refinement, however, it’s been a quietly impressive convertible, with a muscular but easy-going character. For 2023, it’s been given a very light facelift. Has it also evolved into a sharper driver’s car? We’ve revisited the Z4 to find out. 

Changes for 2023 are subtle: the hexagonal pattern within the grille is peppered with horizontal floating inserts (with a shinier, 3D effect on the M40i), and flanked by new air intakes and redesigned fog lights in the front bumper. There’s a little more gloss-black trim at the rear too, but it’s a light-touch on the visual update side. 

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As before, the Z4 is offered with two engines: 2-litre four-cylinder turbo, or 3-litre straight-six turbo, tested here in the range-topping BMW Z4 M40i. In 2018, there were two 2-litre variants with different levels of power, the 20i and 30i, and multiple trim levels, but the UK range has since been streamlined. There are now just two Z4 variants: the 194bhp 20i M Sport, and the 335bhp M40i. As before, both use an eight-speed torque converter auto gearbox.

The 20i starts at £44,490 at the time of writing (October 2023), compared with around £37k back in 2019. The M40i costs £56,475. Its most natural sparring partner, the Porsche 718 Boxster, starts at £53,800 and its platform-sharing fixed-head coupe twin, the Toyota GR Supra, from £50,545 in 254bhp 2-litre guise.

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The Z4 M40i’s straight-six is still a lovely engine to spend time with. A rich seam of torque is available from low down, giving the M40i a strong turn of pace (and helping to combat its circa. 1600kg kerb weight) and while it’s not the loudest of engines, it makes a muted but pleasant, mellow bellow.

That contributes to the Z4’s impressive refinement, roof up or down. Previous experience in the pre-facelift Z4 says that even at autobahn cruising speeds with the roof open, there’s very little buffeting. The standard-fit (and collapsible) wind deflector bridging the two rollover buttresses does a very good job. 

The roof itself whirs open and shut rapidly while the car’s travelling at speeds of up to around 30mph; handy if you’re caught in a cloudburst. Roof-up refinement is impressive, too. There’s a bit of road noise from the broad tyres (grippy Michelin Pilot Super Sports in this case), but that’s to be expected, and otherwise the Z4’s cabin is a relatively serene capsule at speed. Aside from being able to position the driver’s seat commendably, floor-scuddingly low if you want to, the Z4’s interior feels as much like that of a saloon as a sports car: lots of kit, lots of places to put things, big dash, big screens. 

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The main touchscreen is controlled via BMW’s slightly older iDrive system rather than the latest 8.0 OS in cars such as the iX. That might be a drawback to some tech-conscious buyers, but for luddites like me who find the new system (which does away with some physical buttons) awkward and confusing to use, it actually feels a bit of a luxurious relief to be able to return to the old system.

There’s space for your phone and two big cup holders under the centre armrest, and a decent boot makes the Z4 a relatively practical car. Apart from the leather for the standard-fit M Sport seats and door trims being finished in a particularly vibrant Magma Red on this particular car, it’s not a very memorable or sports car-esque interior. That said, it’s pleasant and comfortable with impressive fit and finish, and what it might give away in a sense of occasion it pays back in long-distance comfort. Ironically for a sports car, the Z4 is an excellent motorway car for long journeys, which perhaps says a little about where its balance of strengths still lies. 

It is fun to drive; the electronically controlled M differential fitted to the M40i as standard does a good job, the torque-rich engine can make it an enjoyably tail-happy (but still safe) car when you want it to be, and there’s plenty of front-end grip too. It’s only when you really press on that you can feel that it’s a convertible and the commensurate shortfall in torsional rigidity begins to make itself known. 

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Electronically controlled dampers are now standard across the Z4 range, and you get the sense they’ve been recalibrated since the car’s launch. They worked very well on the pre-facelift M40i but the ride never quite settled down, even on smooth roads. Now, in Comfort mode, it feels much smoother.

The ride is still a bit too brittle for me in Sport mode, and likewise the steering becomes a bit too stiff and sudden in response in the same setting; but that’s in the eye of the beholder/hands of the steering wheel holder, and you can mix and match driving modes. 

As is the design, which to my eyes looked bold but slightly awkward and jarring at launch, but has aged better, with the squat roadster proportions and subtle nods to the classic 507 becoming more evident. The matt Frozen Grey paint applied to the car tested here is an £1880 option.

The Z4 in general is a car that can leave you slightly cold on first encounter, as it did me at its launch. But the more time you spend with it, the more its strengths make themselves known. I ran a Z4 for six months as a long-term test car in 2019 and have a lot of affection for it as a result. There is a place for cars like this; smaller and cheaper than a Mercedes SL, more easy-going than a Boxster. 

It is more a cruiser than a sports car, but it is a sports car nonetheless. The joint-venture platform-sharing Toyota Supra is the more stirring driving experience of the two cars, but the Z4 M40i is still a solid drive with an enjoyable engine and well-calibrated electronics for its dampers and diff. 

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Price and rivals

Today, it’s kind of been left in a class on its own. The Mercedes SLC has gone, the Audi TT Roadster is about to cruise into retirement. Maybe there’ll be a new era of electric two-seater convertibles in the mould of the MG Cyberster but until then the Porsche 718 Boxster is its closest on-paper rival. The Mazda MX-5 is more affordable (and fun) but less potent, less roomy and a car from the class below.

In reality, the £56,475 Z4 M40i is never going to be as fun as a Boxster to drive (despite insiders stating that the Porsche was the Z4’s dynamic benchmark in development) but its strengths are in different areas. The M40i engine is more enjoyable company than the flat-four in base-level Boxsters (and you have to pay £75k for a Boxster with a six-cylinder engine, the – admittedly brilliant – GTS 4.0).

The pre-facelift Z4 is a car I remember fondly, but more for its easy-going nature and enjoyable engine than for memories of thrilling drives. On the basis of a brief test in this 2023 model, that’s still the case post-facelift.

BMW Z4 M40i specs