The 350Z has started to transform Nissan’s image, bringing back the heritage of its classic Seventies 240Z and 260Z sports cars and consigning the image of dull Eighties Talbots to the bin.

AM was impressed when it originally drove the coupé, describing it as offering a “sporty but refined ride with excellent handling”. But what about the roadster?

Conventional wisdom has it that cars transformed from coupé to soft-top lose much of their sporting prowess because the body flexes more, and in order to address that (and to satisfy safety legislators), pillars have to be strengthened, which adds weight and affects handling.

Instead, like the MX-5 or MR2, they need to be designed and produced as a convertible.

That’s the wisdom, but with the 350Z roadster the rulebook can be torn up. The stiffer body all but eliminates body shake and adds around 110kg (at 1,644kg) to the weight of the coupé, but that’s not a concession to performance.

The sprint to 62mph is only slightly slower – 6.4sec versus 5.9sec – while handling is just as sharp. And, of course, it still has the thrilling burble from the 3.5-litre V6, thanks to careful retuning of the exhaust note.

The roof opens in a speedy 20 seconds and is neatly stored away under a lightweight tonneau cover in front of the boot lid. Luggage space is reasonable (130 litres) with the top down – though few people buy roadsters to cart luggage about.

Nissan has paid special attention to wind noise, developing an S-shaped rubber section that creates a tight seal around the side windows, while a triple locking system tightly secures the roof to the windscreen.

It works – to a degree. Noise is lower than in some rivals, but still cannot match the coupé.

Nissan expects to sell 600 roadsters this year, and forecasts a similar number in 2006, which should ensure strong residuals. Some of these will be cannibalized from coupé sales – last year that model sold 2,248 in the UK; this year and in 2006 the target is 1,700.

Strengths: Looks, performance, engine
Weaknesses: Uninspiring interior
Opportunity: Supplementary sales
Threat: Serious hot rivals
The USP: Tearing up the rulebook for coupé convertibles
Price: £27,000
Engines: 3.5-litre V6, 276bhp @ 6,200rpm
Performance: 0-62mph: 6.4sec; top speed: 155mph
Transmission: Six-speed manual
Efficiency: 24.1mpg; 280g/km CO2
CAP RV 3yr/30k: £14,175 (51%)
Rivals: Porsche Boxster, Honda S2000, Mazda MX-5