2025 (25) BMW 4 Series 420i M Sport 2dr Step Auto

BMW's second generation 4 Series Convertible has more appeal in this improved form. Jonathan Crouch takes a look.

Ten Second Review

The improved version of BMW's second generation 4 Series Convertible now has an even more distinctive look and a sporting dynamic feel. Inside, there's now more media tech and an even plusher cabin. The range has been severely slimmed down in this updated form, but for brand enthusiasts, there's still plenty to like. You won't get the large boot and cutting-edge driving dynamics of the 4 Series Coupe, but compensations come in the form of refinement, security and drop-top desirability. You'd like one.

Background

Echoing the bold style of its 4 Series Coupe showroom stablemate, the improved version of BMW's second generation 4 Series Convertible aims to blend sporting driving pleasure and open-air thrills to continue the 40-year legacy in this model class that began with the Munich maker's first 3 Series Convertible. As before, it sizes up to the same two segment arch-rivals, Audi's A5 Convertible and what's now called the Mercedes CLE Cabriolet - and like those competitors uses a fabric roof. With this smarter revised model, plenty of changes under the skin aim to make it a bit more of a driver's car than before.

Driving Experience

BMW has worked hard to ensure that this 4 Series Convertible's handling is as close to that of the equivalent Coupe as possible, using extra bracing and special panels to improve body rigidity. As usual with this model range, there's rear wheel drive and xDrive 4WD for the fastest models. There are no dynamic or engineering changes for this updated model, but BMW has slimmed down the powerplant range considerably, discontinuing diesel power and dropping the previous mid-level 430i petrol variant. That leaves only two mainstream models; the base rear-driven 184hp 420i; and the six cylinder 392hp M440i, which only comes in xDrive 4WD form. That six cylinder engine also features in 530hp form in the flagship M4 Competition variant, also only offered in xDrive guise. As before, there are firm springs and anti-roll bars, plus this Coupe gets a double-jointed spring-strut front suspension and a 5-link rear axle. All the engines link up as standard with eight-speed Steptronic auto transmission, which incorporates Launch Control for Grand Prix-style getaways. As previously, the M440i gets a Sprint function that gives you a steering wheel paddle that when activated, gives you an extra burst of acceleration. Toupees will need to be very firmly tied down. Arguably, less is more here - it's the rear-driven 420i that gets closest to BMW's traditional mid-sized coupe driver's formula. Rivals have long tried to copy this variant's front engine, rear wheel drive BMW layout with its near perfect 50:50 weight distribution - but never quite managed to deliver a package with the same kind of involving finesse. Super-effective traction and stability systems keep those back wheels in check so that if you're not a driving enthusiast, it'll all feel quite normal. But if you are, then the feeling of being propelled up the road by the back wheels as you exit a bend rarely fails to offer up a great feeling of pleasure.

Design and Build

When this MK2 4 Series Convertible first arrived, we were all talking about its rather inevitable switch from the previous model's metal hard top roof to the same kind of folding fabric top that rivals Audi and Mercedes offer. That meant a 40% reduction in roof weight from a soft top that uses panel bow elements and a glass rear window for optimum acoustic and thermal comfort. The electric folding roof takes 18 seconds to open or close and can be used at speeds of up to 31mph. With the revised version of this MK2 model, BMW wants us to talk about the car's redesigned LED headlights, with their smarter illumiating signature. That once-controversial grille is now surrounded by matte chrome and there are restyled front and rear bumpers too. Customers can add in the 'laser' rear lighting units first seen on the rare M4 CSL, plus there are restyled 19-inch wheel designs. And the top M440i gets black exterior design elements and horizontal bars within the kidney grilles. The CLAR mixed steel-and-alloy platform that underpinned the previous version of this car is retained, but BMW has tried to reduce its weight through greater use of aluminium panels. Inside, the air vents have been redesigned, as has been the steering wheel, which is now flat-bottomed and has standard shift paddles for the auto gearbox. As before, the 'BMW Live Cockpit Professional' dash set-up is standard, offering a fully digital screen layout that gives you a high-resolution 12.3-inch instrument cluster behind the steering wheel and a 10.25-inch iDrive infotainment Central Control Display, which now runs the brand's latest OS 8.5 software system, which gives you more customisation options. There's also enhanced voice control for the climate functions. As before, this is billed as a 'proper four-seater', though the rear seat isn't as comfortable as in the Coupe. Predictably, there's not as much boot space either, the Coupe variant's 440-litre capacity figure falling to 385-litres with the roof closed and 300-litres with the top down.

Market and Model

Sporty 'M Sport' trim is standardised and prices start from around £53,000 for the entry-level 420i, which means a big price premium of almost £7,000 over the equivalent Coupe model. Think in terms of around £70,000 if you want the M440i xDrive model. The top M4 Competition Convertible M xDrive model is around £95,000. Equipment levels have been subtly upgraded. Ambvient lighting's now standard and upholstery comes in a new velour the brand calls 'M Performtex'. Optional is Sensatec perforated manmade leather - or real quilted Vernasca leather. Interior trim strips in Aluminium Rhombicle Anthracite are standard, whilst Fineline Light Brown open-pored and Grey Blue Ash open-pored fine-wood trim, and M interior trim carbon fibre are available as options. Customers can also now have the gear selector lever, iDrive Controller and Start/Stop button in a 'CraftedClarity cut-glass finish. A Personal eSIM comes as standard with the car, in addition to its built-in mobile SIM. This enables the vehicle to use the 5G mobile communications standard. The Personal eSIM allows the customer to use the communications and connectivity functions covered by their mobile contract from their car with ease - even in situations where they don't have their smartphone with them. This also includes data streaming via the WiFi hotspot. Wheel sizes vary between 18 and 20-inches and among the options are an M Performance front ornamental grille and M Performance side sill attachments, both in carbon fibre. Interior equipment highlights include the M Performance seat back pans in Alcantara/carbon fibre, the M Performance interior trim strips in carbon fibre and the M Performance door sill trims, also in carbon fibre.

Cost of Ownership

As before, mild hybrid technology is included with both the mainstream engines. Fitting a 48V starter-generator and second battery greatly increases the scope for utilising Brake Energy Regeneration and the electrical power it produces. The recuperated energy collected by the 48V battery can be supplied to the 12V electrical system or used for generating additional drive power when fed back to the 48V starter-generator. When the car is accelerating, the generator is also able to offer the driver an electric boost effect that instantly makes an extra 11hp available. All of which should promise a very competitive set of efficiency stats. Let's see. The 420i is rated at between 46.3 and 49.6mpg on the combined cycle and 140-131g/km of CO2; for the six cylinder M440i xDrive, it's 38.2-40.9mpg and 169-159g/km. For the M4 Competition xDrive Convertible, it's 27.7mpg and 231g/km. Residual values? Well we expect the depreciation on this facelifted second generation 4 Series Convertible to be pretty similar to that of its direct predecessor, which would mean a very competitive retained worth of about 45% after three years and 60,000 miles. On to the warranty package. BMW's warranty only lasts for three years but it includes an Emergency breakdown service and at least it isn't mileage limited - unlike the comparable package you'd get as standard with a rival Audi. You can of course extent the warranty with either monthly or annual payments. There's a three year paintwork warranty and the usual 12 year anti-corrosion warranty.

Summary

Like many of its owners will be, BMW is quietly satisfied with this 4 Series Convertible, especially in this revised form. Would this car be a more engaging driving machine without the extra weight of its roof mechanicals? The extra sharpness of its 4 Series Coupe stablemate certainly suggests that. I sense though, that most buyers of this open-topped version will be quite happy with a more relaxed, comfortable demeanour. That is, after all, as much as competitors from Audi and Mercedes offer - and those brands can't deliver the engine choice BMW provides here. In fact, a lot of boxes are ticked by this car if you can afford its asking price. You get impressive safety systems, high residual values, above average rear seat legroom and a sheer depth of engineering that rarely fails to impress. As a result, in many ways, it's probably the most complete contender in this segment and, best of all, it looks as striking and expensive as a convertible of this kind should when the sun's out and all is right with the world. True, there are probably all kinds of ways of more sensibly spending the budget required for one of these. You know what though? Right here, right now, I can't really think of any....