RENAULT has made great claims about the improved torsional rigidity of the new Megane Coupe-Cabriolet compared with its predecessor, but in only the short distance in which we were able to experience the car with the roof down, there was still discernible twisting on the launch drive.

It was doubtless less extreme than in the earlier car, which was quite poor in this respect, but our first impression is that it is still only a little better than average across the market for body stiffness and rigidity. It will not be sending the Porsche engineers back to their drawing boards.

With the roof firmly locked in, the Coupe-Cabriolet felt reasonably rigid, albeit with the occasional moment of flex making itself evident. A longer period behind the wheel and over more demanding surfaces is required, but the Megane seems stiffer than many other vehicles in its class and certainly so with the formidable roof erected.

The element of its on-road behaviour from which there was no escaping, though, is engine/transmission performance.

Frankly, this solid little pleasure vehicle is now under-engined. What it needs is one of Renault’s zesty turbodiesels, not an ageing 103kW 2.0-litre petrol four (even if it is Euro 5 compliant) or, for that matter, how about the outstanding 184kW unit used in the Megane Renault Sport 250 to add real ‘sports’ to the delightful ability to go top-down?

It is difficult to see, for example, how Renault can justify having the Coupe-Cabriolet accelerate from zero to 100 km/h in almost 12 seconds, where sub-10s are closer to current expectations.

Obviously the importer has to weigh-up what the market wants and chose the CVT over a six-speed manual but – even accepting that you can now order the Subaru Impreza WRX STi as an automatic, such is the fast-declining demand for manual gearboxes and clutch pedals – the unappealing drone of a hard-working CVT is a disappointment.

Cruising serenely, this is an acceptable device, but it does not invite hard driving. No, it is wiser to crank up the formidable audio and enjoy the world.

The chassis seems well up to the task of press-on driving, feeling nicely balanced and responsive to steering inputs, with the same excellent feeling and weight at the rim as the hatch and Fluence. The braking, too, is first-class, thanks to the same immense 280mm front and 260mm rear disc rotors.

Plenty of work has gone into adapting the suspension and steering to the twin tasks of aiding structural integrity and supporting significant additional mass.

Renault claims that the engine subframe’s relationship with the body structure is three times as rigid as on the previous model, spring stiffness is up 13 per cent at the front and 17 per cent at the rear, the anti-roll bar is almost 50 per cent stiffer, body roll is said to be much-improved over the old CC, the rear beam is about 25 per cent stiffer and the dampers are stiffer but the bump stops are softer in the interests of ride comfort.

The result of these changes is that the CC rides a little more firmly than its hatch and sedan counterparts but, like all Meganes, copes well with large bumps and irregular surfaces.

Swapping the CVT for the six-speed manual offered in other models would doubtless add greatly to the driving experience, but many buyers will be much more interested in the cool image this Renault effortlessly conveys without even needing to turn a wheel.