Broadcast dates : 30th May 2004/3rd June 2004

Last week we brought you Hendrik's impressions of the new BMW 645Ci Coupe, a car that is likely to be bought for its beauty as well as its lusty, sporting performance.

This week we preview the convertible version of the 645Ci, which was officially launched in South Africa three weeks ago. In fact this preview was filmed using a left-hand-drive version, but the right-hand-drive models are already here.

It is in the styling that the reason for the 645's existence needs no explanation and that goes double for the convertible version.

Interestingly enough it is not always easy to create a good-looking convertible from a closed roof car. Simply lopping the top off a car can sometimes ruin the proportions. But with this one, BMW has got it right.

Running your eye over the 645 Convertible’s lines also serves to clarify the direction in which BMW's styling team has been going in the past few years.

The past few large volume BMW models, particularly the 7-Series sedan, have come in for a lot of criticism, even from hard-core BMW devotees.

The master stroke of this Six-Series convertible is that it manages to integrate many of these themes from the past few years into a very harmonious whole.

Particularly graceful is the frontal treatment with the hooded predatorial headlights leading the eye inwards to the clean, crisp rendition of the traditional BMW twin kidney grille.

Aggression is there too in the sharpness of the lower air intakes, hinting that this indeed is a car to be taken seriously.

The 645 Convertible is no lightweight, weighing in at over 1 600 kg, although for a car this size that is impressively light. Like the Coupe, the convertible makes use of a front end, forward of the driving compartment, that is crafted in aluminium.

And there are many lightweight composite plastic materials used, including the bootlid.

Yet for a large convertible the car is extremely wieldy on twisty roads. This is where the Active Steering system comes into its own.

Active Steering, standard on the 645 Convertible and Coupe models, effectively makes the steering more direct at low speeds, such as you would experience in a tight mountain pass.

Less turns are required to turn the steering wheel from lock to lock, or full right to full left position.

Then as speed rises, the steering ratio is progressively lowered, so that you have relatively indirect steering at high motorway speeds. This is to make the car less twitchy at high speeds, making for a more stable and relaxed experience.

The convertible top is of fabric, BMW feeling that the complexity of a steel roof was not what its customers wanted in this car. The fabric top is nevertheless fully automatic in operation and can also be raised and lowered at speeds up to 20 km/h. Handy in the event of a sudden shower when you were enjoying the fresh air.

Styling wise, the top is also very attractive, featuring twin side fins, or strakes, at the rear, much like the Jaguar XJS steel roof of the 1980s.

From a styling point of view, this balances the roof with the length of the boot and the stowage area for the top.

Incidentally, the Fabric top uses a very special headlining technique in the interior making it possibly the quietest fabric-top convertible ever produced, when the top is in place.

Another foxy feature of the top is the sliding glass rear window. This slides up from behind the rear passenger seats and seals snugly against the fabric top. However, it is possible to drive with the top in place but the glass retracted, to provide a bit of fresh air and stale air extraction.

The cockpit is a mix of style, luxury and a hint of aggression. That chunky steering wheel with the large black centre portion speaks of sporty motoring, and the 645 Convertible is no slouch in this department.

Just as the 330 Convertible is the most solid in its class, so is this 645i Convertible. With the top down the body remains as rigid as many steel-roofed cars.

It is also possible to drive the convertible very hard with very satisfying results. Dynamic Drive suspension, which controls body roll to a minimum and choice of either 18 inch or 19 inch alloy wheels with 245 series rubber at the front and 275s at the rear makes this a heavyweight with a deft touch.

Like the 645Ci Coupe, the 645 Convertible is available only with a 4,4-litre all-alloy, 32 valve V8 motor. Fitted with variable valve timing, this V8 recently scooped a fistful of international awards for engineering excellence, notably as it has in fact been in production for a few years now.

It is a free-revving unit capable of spinning to 6 500 rpm, and produces two hundred and forty five kilowatts. Torque is rated at four hundred and fifty Newton metres.

Like its closed-coupe counterpart, it will break the six-second barrier in the zero to one hundred kilometres per hour sprint, and run two hundred and fifty kilometres per hour in sixth gear.

And like the coupe it comes with three gearbox choices: manual, paddle shift and automatic, all of them six-speed units.

BMW isn't looking to flood the market with this car and in fact just one hundred examples per year are expected to be imported. But we are sure demand will be much greater than this.

The BMW 645Ci Convertible costs R736 000 in manual form, R749 000 for the paddle shift or SMG gearbox, and R750 000 for the automatic.

Our choice would once again be the automatic for a car of this nature.

It is all about refined, seamless cruising with loads of power on tap at any time.

For this, the six-speed automatic version is the perfect choice.