The new Aston Martin Vantage Roadster is one of the most powerful drop-top sports cars on sale following an extensive, performance-focused upgrade.

With 656bhp and 590lb ft from a reworked version of the existing twin-turbocharged 4.0-litre V8, the new Roadster packs substantially more power than its 505bhp predecessor and has been set up to be a more dynamic proposition.

Now more powerful than rivals such as the Porsche 911 Carrera 4 GTS Cabriolet and Ferrari Roma, the Aston’s new power levels even push it to vie with some models in the class above, such as the Maserati MC20 Cielo and McLaren Artura Spider.

The new drop-top follows the coupé that was launched nearly a year ago and was described by Aston as “the most driver-focused and fastest Vantage in the famous nameplate’s 74- year history”.

The Vantage Roadster draws power from the same Mercedes-AMG-derived powerplant as the coupé. Although the convertible is 60kg heavier, due to its extra rigidity bolstering and roof mechanics, it can still match its sibling in a straight line with a 0-62mph time of 3.5sec. Top speed for both is limited to 202mph.

That makes it as fast as the outgoing 690bhp V12 Vantage Roadster, the most powerful drop-top Aston has produced to date.

The car’s pace is the result of an “extensive” overhaul of its V8. Aston has added new cam profiles and larger turbos, tweaked compression ratios and improved cooling. The firm has also adjusted the ratios and calibration of the eight-speed automatic gearbox for “punchier” in-gear acceleration and quicker gearchanges.

To improve driving dynamics, the aluminium chassis has been stiffened and work has been done to keep the car at a near-50:50 weight distribution. As before, double wishbones are fitted at the front and multi-link at the rear.

Aston claims the car’s rear end is up to 29% stiffer under load, to the benefit of handling and driver feedback. New bespoke-tuned Bilstein DRX adaptive dampers also increase responsiveness.

There is a choice of steel or carbon-ceramic brakes and its standard 21in alloy wheels are shod with bespoke Michelin Pilot Sport S 5 AML tyres.

Aston claims the new convertible has the fastest-folding roof on sale today.

The cloth top opens or closes in just 6.8 seconds and can be operated at road speeds of up to 31mph. For comparison, the Roma Spider’s takes 13.5 seconds.

The new car is visually marked out from its predecessor by a revised front end – notably with a larger grille – and a 30mm increase in width.

Inside, it mirrors the Vantage Coupé, which ushered in a completely new cockpit arrangement. The cabin gets a 10.25in touchscreen, wireless smartphone mirroring and an array of buttons, switches and dials for the most used functions.

Pricing has yet to be announced, but Autocar understands it will start at around £175,000, a £10,000 premium on the coupé. Deliveries begin in April.