Review of the new BMW Z4 Roadster

BMW has all the ingredients to make a great roadster and this second generation Z4 is an impressive attempt at pulling them together in a compelling fashion. With a more conventionally attractive look than its predecessor, a folding hard top roof and a predictably polished engine range, this has proved to be the BMW's best stab yet at class leadership.

BMW set itself quite a challenge with the second generation Z4 roadster we're looking at here. The Munich brand is never shy of reminding us of its claim that it builds 'the ultimate driving machine' but you might think that a boast unlikely to be underlined by equipping this car for the first time with a heavy folding metal roof. Were this model's closest competitor Porsche's fabric-topped Boxster rather than the metal-roofed Mercedes SLK, BMW might have been able to resist the fashionable demand for automotive metal tops that flip down like Swiss army knives. As it is, the Z4 simply had to have one to properly compete. And as usual, BMW has done the best possible job with the tools available. Let's see how they've done it.

Sound and styling are everything when it comes to roadster motoring and most will feel that this Z4 delivers on both counts. All four six cylinder petrol engines certainly satisfy on the aural front, whether you choose the 204bhp 2.5, the 258bhp 3.0-litre or the 306bhp and 340bhp twin-turbo 3.0-litre units. From the crackle at start-up to the metallic-edged bark under hard acceleration, this Z4 sounds race-bred.

Better still, the inherent good looks of the first generation version haven't been unduly harmed by the adoption of a folding aluminium roof that weighs only 30kgs and therefore doesn't unduly harm performance that sees this sDrive 35i model race from rest to sixty in just 5.2s on the way to an artificially limited top speed of 155mph. That's faster than a Porsche Boxster S if you're interested.

Unlike the 3 Series Convertible, the first car BMW made with a metal folding roof, this Z4 has managed to retain the German brand's famed 50:50 weight distribution with the roof up but ironically, it's with the roof down and the extra weight over the rear wheels that it feels most responsive. There's virtually no body lean and in the dry at least, you rarely run out of grip. Most owners will want to pay around a thousand extra for the Adaptive M Sport Suspension I have here which enables you to adjust the dampers depending on the driving conditions. Most of the time, you'll only use two settings - 'Normal' and the stiffer 'Sport' - but there is also a 'Sport+' setting which lowers the car by 10mm, firming things up still further for racetrack use and offering 10% more driver leeway before the stability control cuts in.

"BMW has been building roadsters for over 75 years - and it shows with this car."

All Z4s come with BMW's Drive Dynamic Control system. Here, you can set your car up to your own preferences, just like a race team would on a racecar. That means altering the response of throttle, steering, stability control and even the gearchange times if you've opted for the six-speed auto that's available on the 23 and 30i models or the full-blown 7-speed twin-clutch transmission offered on the 35i variant and standard on the 35is. It all works brilliantly, though the steering can still feel a little lifeless, no matter how you tweak it. This car had to replace coupe as well as roadster versions of the MK1 Z4, so roof up, refinement had to be peerless: it is. Roof-down of course, it's very different but many will see the blustery feel as part of the fun of owning a car of this kind.

You'd expect the change from fabric to metal-top roof to have altered this Z4's appearance a good deal more than it has. There are no awkward looks, no tell-tale bulky rear end. In fact, you've to look twice to recognise this second generation car, despite the fact that it's slightly wider and 120mm longer than its predecessor. Of course, clever as BMW's designers are, they couldn't do miracles. As you'd expect, the solid roof has brought a heavier kerb weight (up by 185kg) and a reduction in boot space (to just 180-litres with the roof down). Still, it's no worse than its arch-rival, Mercedes' SLK in this respect and the Z4 has the advantage of being able to boost its 310-litre roof-up capacity via an optional ski-flap in the boot. Thus equipped, you could carry either a couple of sets of skis or, more ambitiously, a couple of sets of golf clubs.

Annoyingly, you have to pay over £500 extra for the 'Comfort Access' option which enables you to raise this folded roof sandwich slightly to get hold of bulky stuff you put in the boot when the roof was up but which otherwise becomes trapped there when the roof is down. Many owners will want to avoid this problem by using the 15.5-litre interior storage area behind the seats. Otherwise, irritations are notable by their absence, unless you count the fact that the folding roof, which electro-hydraulically raises or lowers in just 20 seconds, can only be used when stationary. As you'd expect for the premium money being asked, everything is beautifully built from the highest quality materials. Plus the extra head, shoulder and elbow room that have been built into this MK2 Z4 model give it a far airier cabin feel than rival Audi TT or Mercedes SLK competitors.

List prices suggest that, allowing for a few well-chosen extras, you'll probably be paying somewhere in the £30,000 to £40,000 bracket for your Z4, the same kind of money Mercedes will ask of you for a comparable SLK but slightly more than you'd pay for a fabric-topped Audi TT Roadster. If you're comparing pricier versions against Porsche Boxsters, you'll also find there's not that much in it. In other words, for this kind of cash against rivals this strong, BMW had better be good.

Whether you choose sDrive 23i, sDrive 30i, sDrive 35i or sDrive 35is six cylinder models, equipment levels offer most of what you would expect at this price point. Alloy wheels, stability control, dual-zone air conditioning, power for windows and mirrors, the usual full complement of six airbags, plus beady Xenon headlamps. There's also an M Sport package that includes the usual racey styling modifications. Otherwise, it's off to the endless options list which could easily see you spending £4-5,000 more than you intended.

These days, even barnstorming sports cars need to keep running costs in check while treating the environment with kid gloves. The Z4 does a better job of this than you'd credit for a car in such a lofty performance bracket, mainly thanks the BMW's EfficientDynamics programme. This takes the form of a collection of innovations which improve a car's efficiency. There's Brake Energy Regeneration, low rolling resistance tyres, light weight design and optimal gear shift indicator lights. The results include creditable fuel economy figures of over 33mpg for the sDrive23i and sDrive30i models with 199g/km CO2 emissions. This sDrive 35i returns 31mpg and 210g/km, the same as the sDrive 35is. In all cases, fitment of an automatic gearbox fractionally improves economy and cuts CO2 output. Expect strong residuals in the 35-42% bracket after 3 years or 36,000 miles.

So how to sum up? Well, first-off, BMW has been building roadsters for over 75 years - and it shows with this car. If you're looking for a premium product in this sector that's more dynamically adept than a Mercedes SLK but not quite as demanding as a Porsche Boxster, it's just about perfect, providing you're a fan of metal folding roofs. But does this constitute the 'Ultimate Driving Machine'? Well, that's something enthusiasts will argue over all day, depending on their definitions of the term. One thing's for certain though. This is one Z that'll be very hard to catch.

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BMW Z4 28i sDrive M Sport 2dr Auto Roadster
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