The softly-sprung E-Class has always made more sense as a Cabriolet than a Coupe. With space for four adults to sit in comfort, a decent-sized boot and classy interior, the only thing it really lacked was power.
That's why Mercedes has decided to introduce a new range-topping petrol version. The all-new 329bhp 3.0-litre V6 engine is the same unit we recently drove in the E400 Coupe, where it also pumps out 354lb ft of torque.
What is the 2014 Mercedes E400 Cabriolet like to drive?
The new engine really suits the E-Class Cabrio's relaxed character and is easily the most punchy and refined version of this car we've tried.
The E400 sounds great at high revs, but the crisp throttle response and huge reserves of torque (all 354lb ft arrives from 1400rpm) mean you can make swift progress. Push the throttle farther and the seven-speed auto gearbox kicks down a gear, both turbos kick-in and the car feels seriously quick.
In fact, with a 0-62mph time of just 5.3 seconds, it's only a tenth slower than the E400 Coupe, meaning it's quicker than its rivals from both Audi and BMW in a straight line.
Drive the E400 with vigour through a series of tight corners, though, and it quickly becomes flustered. The body leans quite a lot, and quick changes of direction cause the car to get out of shape quite easily. It's definitely more suited to cruising than hustling along country roads.
That said, the nicely weighted and accurate steering provides all the feedback you need to corner with confidence.
Confronted with a smooth road surface, the standard adaptive dampers do a fine job of keeping the Merc's body controlled over crests and cambers. However, the E400 feels quite unsettled over pockmarked roads, and tends to thump over drain covers and potholes. There's a bit of flex in the body, too, and sharp-edged bumps are all too easily transmitted through the steering wheel.
The roof mechanism is a bit slow to get going, but can be used at up to 25mph, and despite using a fabric hood rather than a folding metal hard top, the E-Class Cabriolet is pretty refined with the roof up. All four passengers are sheltered from buffeting with the roof lowered thanks to the standard Aircap system – a flap on top of the windscreen that deflects air over the cabin.
What is the 2014 Mercedes E400 Cabriolet like inside?
As plush as you would expect for the price. Despite its recent face-lift, the E-Class's cabin is beginning to look a bit dated, although there are still plenty of high-quality materials on display. The switches are all nicely damped, and because it's only available in range-topping AMG Sport Plus trim, the E400 gets a huge amount of kit as standard.
That does make it look expensive next to rivals including the 435i Convertible, but everything from the heated leather seats, to the excellent Harman Kardon stereo and three-spoke sports steering wheel comes included in the price – you won't need to tick a single option box.
The centre console is a little cluttered with buttons, but navigating the Comand infotainment system is relatively easy, and the rotary dial controller positioned between the front seats is easy to use while you're on the move.
There's quite a lot of space inside, too. A six-foot passenger will be able to sit behind a tall driver in relative comfort, and in the front the electrically adjustable sports seats are very comfy.
Its compact fabric roof means you can still carry 300 litres of stuff in the boot with the hood down. That's easily enough for weekend bags or shopping and a lot more space than you get in, say, a BMW 4 Series Convertible.
Should I buy one?
The wonderful new twin-turbo engine gives the E400 Cabriolet real charisma and muscular performance. Sadly, the chassis can't always keep up. This isn't a particularly sharp car to drive, yet on on rougher roads, the 19-inch alloys and firmer AMG Sport Plus suspension combine to give the Merc a shuddery ride.
Still, the E400 is a refined, classy and spacious four-seat drop-top that's reasonably practical, with running costs that are competitive with its closest rivals' and a huge amount of kit. There aren't too many many other options to choose from at this price, so it's a tempting choice.
What Car? says...
Engine size 3.0-litre V6 turbo petrol
Price from £49,645
Torque 354lb ft
0-62mph 5.3 seconds
Top speed 155mph
Fuel economy 35.8mpg
CO2 output 185g/km