Alfa Spider V6 Q4

British buyers will get their first glimpse of Alfa's new convertible at the Motor Show. Its soft top marks it out as a true sports car

Price: from £30,250 approx (range will start at about £24,300). On sale January
Engine: 3,195cc, V6 cylinder, 24 valves, 260bhp at 6,200rpm, 237lb ft at 4,500rpm
Transmission: six-speed gearbox, four-wheel drive
Performance: 146mph, 0-60 in 6.8sec, 24.6mpg official average
CO2: 270g/km

The scirocco has been blowing like dragon's breath here in Sicily. Last night, the boats were clashing in the marina. Flowerpots flew and windows banged. Today, it's like stepping out into an oven.

I'm driving a new Alfa Spider along sinuous, bumpily structure-testing Sicilian roads. I am not a mad dog, rather the other creature who dares venture out in the midday sun. We British love open cars much more than Italians do. It's something to do with our scarcer sun-worshipping opportunities; we like to make the most of them, and too bad about the sunburn.

Here's a village called Purgatoria. This sounds ominous. What will happen as we pass through? Indeed, will we pass through or be held forever in some limbo? Bodies, souls and Alfa escape intact. Maybe the effect is delayed. We shall see.

The new Spider is anything but purgatorial. It's based on the fairly new Brera coupé. The Brera is a kind of production version of Giugiaro's delicious Brera concept car, but something was lost when the wheelbase shrank and the overhangs seemingly grew. Seen directly from the side, the Brera has odd proportions. From every other angle, it's strikingly handsome.

Anyway, Giugiaro never conceived the Brera as an open Spider version. The Brera is built for Alfa Romeo by the production arm of the rival Torinese design house Pininfarina, and it is they who devised the convertible conversion, co-designed the look with Alfa's own styling centre, and now builds it.

Note that this is not a Brera Spider, by the way; it is known by the arachnid name only, like its GTV-based predecessor and various previous Spiders.

The new Spider's front half is pure Brera outside and in, and therefore pretty similar to an Alfa 159 too. But the rear end is subtly different: shorter (by 20mm), rounder and with kicked-up haunches. It contains a boot which, while hardly cavernous, is much more useful than the previous Spider's paltry sliver of space.

Alfa says the Spider is a proper sports car, and with its racy windscreen line and two-seat cabin, it has the visual qualifications. Where two small rear seats reside in the Brera are found, here, a shelf and a pair of lockable but shallow lockers. There's also space for the hood's neatly-concealed mechanism and for the hood itself to hide neatly under its shapely cover after its 24 seconds of electro-hydraulic furling. On the return journey the hood, beautifully made up from five layers of fabric, latches automatically and very snugly to the windscreen header rail; there's hardly any wind noise.

A soft top, then. Why, given that so many carmakers are doing hard-roofed coupé-cabriolets now? Several reasons. A coupé - the Brera - already exists. Alfa Romeo believes that a Spider should have, by definition, a fabric convertible roof. And be a true sports car.

To achieve credibility here, though, the Spider needs all the help it can get. Sports cars aren't really meant to have front-wheel drive, and this could be a snag for the cheaper of the two versions, the 2.2 JTS. But maybe these are the puritanical ramblings of someone with roots in an era when cars were cars, not fashion objects. Nowadays, so-called sports cars aren't really used for club-level motor sport because people use hot hatchbacks instead. And they always have front-wheel drive. It's a confusing world.

However, the Spider I'm driving now, as Purgatoria is left behind with no apparent ill-effects, has four-wheel drive with a major bias to the rear wheels, except when conditions dictate otherwise. It also has Alfa's mellifluous 3.2-litre V6 engine with 260bhp; power enough, you would think, to render the Spider's 60kg weight increase over the already overweight Brera not too noticeable.

More noticeable might be the effect of chopping off the roof on body stiffness and driving precision. The signs are not promising: the Spider's torsional stiffness is 64,000dNm/ radian (never mind what the figures mean, just compare them) with roof down, 74,000 with roof up. The Brera's figure is 160,000 - more than double. Still, the Spider is said to be stiffer than a top-down Mercedes-Benz SLK and 25 per cent more rigid than the old Spider.

Figures aren't everything, though. I'm thrilling to the sound and thrust of that V6, heard all the better with the roof down. But where is the precision and tenacity so obvious in the Brera? The front wheels don't bite into a corner with the same zeal. Some bumps provoke a windscreen-wobble not found in an SLK, whatever the figures. The Spider's suspension is softer than the Brera's to minimise disturbance to the structure, so the end result is bound to be more cruiser than sports car. After all, an open car with such a palatial dash (the same as the Brera's) was never going to be a lithe roadster.

So I try the 2.2-litre, four-cylinder version with Alfa's balancer-shaft, direct-injection 185bhp engine, driving the front wheels only. It's the best example yet of this engine, with a clean, even power delivery and really good pull. It has a particularly light, quick and positive gearshift. But that slight structural wobble has bigger consequences in the 2.2; it feels nervous and skittish under acceleration in a way the four-wheel-drive Spider does not.

The new Spider fulfils only part of a sports car's brief to look and sound good. But you can't blame Alfa Romeo for that; it's responding to today's market. Consider: when the roof is down, the air-conditioning automatically alters its operation to keep the fan going instead of trying to maintain a pre-set temperature; an admirable contribution to global cooling. You didn't get that in an MGB.

The rivals

BMW Z4 3.0i SE Roadster £32,765

The new Z4 brought "flame surfacing" to the design lexicon. Smooth straight-six power and rear-wheel drive make it a proper sports car.

Mercedes-Benz SLK 280 £31,000

A Benz that's not overpriced against its rivals. It's a coupé-cabriolet, and thoroughly pleasing to drive, with a V6 engine and rear-wheel drive.

Nissan 350Z Convertible £27,845

The best car here, and the best value, with a lusty V6, great looks, terrific rear-drive handling and almost no shudder. How it should be done.