BMW Z4

BMW has improved the Z4 in nearly every area, and fitting a hard-top hasn’t affected its looks or dynamics. The sharp styling remains, and the two-part roof folds neatly to reveal a more roomy, higher-quality interior. Plus, the 35i engine is superb, as is refinement, and the ride is improved with the optional adaptive suspension. But while it has plenty of grip and pace, and is very desirable, the Z4 isn’t as involving as other BMWs.

IT’S time to lift the lid on one of this summer’s most exciting sports cars! The all-new BMW Z4 now comes equipped with a folding metal hard-top as it takes the fight to arch-rival Mercedes’ SLK.

There’s a choice of three straight-six petrol engines, and bosses say that this – along with the improved space and comfort – will help the newcomer appeal to a broader spread of buyers.

Video: watch CarBuyer's video review of the BMW Z4

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The styling is instantly recognisable, as the Z4 retains the classic long nose and front-engined, rear-wheel-drive layout. Yet while the contrasting surfaces and lines of the original remain, the car is longer and wider than before, and so looks sharper and more elegant.

Crucially, even though it now has to accommodate a hard-top in the boot, the model is tidy and well proportioned. And at the touch of a button, the fully automatic two-piece aluminium roof folds away in only 20 seconds.

The cabin isn’t as claustrophobic as it was – there’s a bigger glass area and more headroom. But the low-slung seat ensures it still wraps around the driver in classic roadster fashion.

Some of the sharp lines of the exterior are mirrored by the dashboard, and quality is first rate, with top-notch materials, a logical driver-oriented layout and classy climate dials.

There’s also more stowage. With the hood up, the boot offers 310 litres of space. This drops to 180 litres once the roof is down, but a new optional load hatch lets you carry a golf bag or skis.

Under the long clamshell bonnet of the flagship 35i we drove is BMW’s fantastic 304bhp 3.0-litre twin-turbo. It’s smooth, refined and powerful, and delivers peak torque from 1,300-5,000rpm, making the Z4 fast and very responsive.

You also get a lovely soundtrack from the twin exhausts, while emissions of 219g/km are lower than key rivals’. The standard six-speed manual gearbox has a slick shift, as does the optional twin-clutch semi-automatic DCT transmission. The latter comes with launch control and well placed steering wheel paddles.

Another first for the Z4 is Drive Dynamic Control, which lets owners adjust throttle response, steering assistance and – on cars with the optional Adaptive M Sport Suspension – damper settings. The latter gives Normal, Sport and Sport+ modes.Sport+ is similar to the previous car’s set-up, so the ride is much better.

Add good refinement whether the  roof is up or down, and the Z4 is a more comfortable cruiser. Yet while turn-in  is positive and body control better, as before the roadster feels nose-heavy and the steering is slightly artificial.

Push hard and the nose soon runs wide, and this tendency towards understeer means the new car isn’t as much fun as other sporty BMWs, like the 335i Coupé. But with its excellent traction and grip, plus strong brakes, the Z4 is more grown-up – and better than ever.

Rival: Mercedes SLK350
WHILE the SLK pioneered the folding hard-top, its roof design is no longer unique and the car can’t match the latest Z4 for handling or interior quality. The V6 offers similar power, but is hampered by its manual box.