Here’s Aston Martin’s next shot at the Porsche 911: a Vantage cabriolet. Caught testing on British roads, the open Vantage will be unveiled this autumn, with first deliveries in early 2007. Expect prices from around £80,000.

Sources say the drop top won’t wear the typical Volante badge; Vantage Roadster is the current favourite. The heavily insulated fabric roof, naturally with a glass rear screen, stows at the touch of a button.

Don’t expect the Roadster to suffer a big weight gain over the 1,570kg coupé. Insiders vow that Aston Martin’s aluminium VH platform is so rigid, it requires minimal extra bracing despite losing the fixed head’s structural rigidity. Aston has overcome one design and engineering challenge, however: seamlessly grafting a saloon boot between those rear wings. For the coupé is, of course, a hatchback.

The Roadster runs the same 4.3-litre V8 as its sibling. Peak output is 380bhp, sent to the rear wheels via a six-speed manual transmission.

Top speed will drop slightly from the Vantage’s quoted 175mph, as the soft top increases drag. Aston expects to build around 1,500 Roadsters a year, around half of Vantage production.

Design

Canvas roof, saloon boot and bespoke rear bumper key changes over gorgeous fixed head Vantage.

Chassis

Roadster spun off Aston’s aluminium VH platform, which is so rigid that only minimal bracing is needed.

Engine

The Vantage’s thunderous, 380bhp V8 will sound better than ever with that heavily insulated roof down