The vast Mercedes-Benz line-up has become a little simpler of late, with the CLK coupe and cabriolet being replaced by new versions badged E-Class.If there is a German equivalent of the Plain English Campaign, it may well be jumping with Teutonic joy.

The vast Mercedes-Benz line-up has become a little simpler of late, with the CLK coupe and cabriolet being replaced by new versions badged E-Class.

If there is a German equivalent of the Plain English Campaign, it may well be jumping with Teutonic joy. The CLK experiment was highly successful for Mercedes, with the rebranded E-Class variants proving more popular than ever, but as much of that was surely down to the quality of the vehicles as it was the allure of a more exotic moniker.

The E-Class badge allows the uninitiated, or those daunted by a list of prefixes, more of an insight into what's on offer in terms of size and the place in the range.

Ironically, as identification has become simpler, the car itself has become more complicated. Always a leader in technology and innovation, Mercedes has not been resting on its laurels with the E-Class Cabriolet.

The big development comes in the shape of the new AirCap system. A simple idea neatly executed, the AirCap extents from the top of the window frame and acts as a frontal deflector sending the airflow arcing over the top of the car and improving interior refinement with the roof down.

It works well, although the effects are more noticeable for rear-seat passengers. There's a much reduced degree of buffeting at speed, extending the options for top-down driving as the reduced air movement within the cabin allows a steady temperature to be maintained using the climate control and, for front-seat passengers, the neck warming AirScarf system. The trade-off is a steady whoosh as air diverts around the device.

Using the same two-door, four-seat layout as the E-Class Coupe, the new Cabriolet has a soft-top roof but with the car's rising belt line it needs only a small piece of fabric to cover the occupants. The Cabriolet manages to retain the same enormous glass house as the Coupe, an impressive feat that aids visibility and gives an airy feel.

Stowing in less than 20 seconds, the roof takes a chunk out of the reasonably accommodating boot space but leaves a delicious profile in its absence. On the way back up it pours in to place in an eerily-hushed manner, with the exception of a reassuring clunk as it hooks into the windscreen frame. Mercedes claims the soft-top offers the same rollover resistance as the fixed-head coupe - an impressive feat.

Three diesel and four petrol engines are available, all boasting the BlueEfficiency badge, with the exception of the range topping E500 V8.

The 3.5-litre 288bhp unit in the E350 CGI seems particularly well suited to the E-Class Cabriolet. Naturally more refined than the impressive diesel units, its performance doesn't fall far short of the range-topping model, all be it without the distinctive V8 rumble.

Mercedes' seven-speed automatic transmission is a key part of its driveability, too. It offers a range of ratios that means the E350 CGI is never caught wanting. Slick changes come quickly when low-speed cruising, upping the pace and selecting the sport option allows the gears to be held for longer, wringing out the power from the top of the rev range. It's reactive enough to negate the need to use the paddle shifters and the responsive chassis can be enjoyed using the fully auto setting.

The light roof and chunky, high-shouldered body means the E-Class Cabriolet feels solid roof up or down, with scuttle shake virtually eradicated and an ability to ride bumps that's within touching distance of the E-Class saloon.

And thanks to a spacious cabin, the impressive level of interior refinement and high-quality materials can be enjoyed by four occupants. A genuine four-seater, the rear can comfortably accept two adults with large doors and automatic sliding seats making it easy to access.

With its high-end specification and clever innovations the E-Class Cabriolet is not a simple car, but adhering to a list of simple qualities such as refinement, good looks and spaciousness makes it simply excellent.

MERCEDES-BENZ E350 CGI CABRIOLET

Price: �40,465

Engine: 3.5-litre, 288bhp petrol

Transmission: Seven-speed automatic, driving the rear wheels

Performance: 0-62mph, 6.8 seconds; top speed 155mph (limited)

CO2 emissions: 206g/km.

Economy: 32.8mpg