The Alfa Romeo 4C has gained a convertible variant via the new 4C Spider.

Unveiled at the 2014 Geneva motor show as a so-called ‘Design Preview’, Alfa says the prototype will translate into a production model in 2015.

The big news with this convertible is obviously up top; the coupe’s hard top has been replaced by a light canvas roof. There is extra structural reinforcement to account for the lack of a closed roof, but Alfa is keen to point out that the use of carbonfibre for the 4C’s rollover bars and windscreen frame has kept weight penalties small. The Spider weighs 60kg more than the coupe, which has an 895kg quoted dry weight thanks to its extensive carbonfibre construction.

Further tweaks for the 4C Spider study include headlights far more stylish than the coupe’s much-maligned items, suggesting a rethink by Alfa that could yield a styling update across the 4C range. There is also a new set of alloy wheels, with ten spokes rather the traditional Alfa telephone dials.

More interesting is the addition of an Akrapovic exhaust system. Part-made from titanium – the Slovenian company’s speciality – it comes with an electronically controlled valve system to adjust the level of noise it emits. One of our biggest qualms with the stock 4C coupe is the rather unattractive noise it can make, so hopefully this new system can fix our quibbles.

Performance is said to match the coupe, with the same mid-mounted 176kW/350Nm 1.7-litre turbo four-cylinder engine sitting driving the rear wheels and yielding a 4.5sec 0-100km/h time and 250km/h-plus top speed.

Officially classed as a prototype, there is no firmer tech details or any word on prices just yet.