The Aston Martin DB9 GT has made its public debut at the Goodwood Festival of Speed.

Set to go on sale globally from September as part of Aston’s 2016-model-year line-up for a price of £140,000, the GT is a last hurrah for the DB9 before it’s replaced by an all-new model (likely to be called DB11) in 2017.

The DB9 GT has 540bhp from its 5.9-litre normally aspirated V12 engine. That’s a significant hike from the 510bhp of the standard car. Peak power from the upgraded engine arrives at 6750rpm, with 457lb ft of torque available at 5500rpm. Power is sent to the rear wheels via a six-speed automatic transmission.

Aston Martin claims the DB9 GT can reach 62mph from rest in 4.5sec and has a top speed of 183mph. Despite the hike in power, only the acceleration figure is an improvement over the standard DB9’s – and even then by only 0.1sec.

Described by Aston product development boss Ian Minards as “the very best of what DB9 can be”, the car sits on double wishbone suspension at the front and rear. Drivers can choose between Normal, Sport and Track driving modes via the car’s adaptive damping set-up.

The GT receives new badges on its exterior, although the most striking modification is its black front splitter and rear diffuser. Carbonfibre tail inserts and new 20in alloy wheels also feature.

Inside, the DB9 GT gets a new generation of Aston Martin’s infotainment system. The touch-sensitive Ami II set-up features redesigned menus and more personalisation options. The car’s leather seats now include the GT badge, and the steering wheel is clad in Alcantara. Interior options include a range of trims and finishes for the centre console, as well as a steering wheel inspired by the One-77.

The DB9 GT weighs no more than the standard DB9 coupé, at 1785kg. In open-top Volante form, the DB9 GT is 1890kg.

Chief creative officer Marek Reichman said: “The purity of form and proportion, together with a lithe, powerful stance, remain at the core of what the DB9 is to look at. With these changes, we have made the DB9 GT yet more elegant while retaining its unmistakable and globally renowned identity.”

Pricing has yet to be revealed, but it’s likely that the DB9 GT will cost significantly more than the £131,995 DB9.

Pitching the car close to the £150,000 mark would allow the new arrival to compete with the Bentley Continental GT Speed (£156,700), which has 626bhp from its 6.0-litre W12 engine, and the Mercedes-AMG S63 Coupé (£125,605), which is powered by a 5.5-litre V8 engine with 577bhp.

The DB9 GT revisits a path that Aston Martin trod with the Virage. Launched in 2011, the 489bhp Virage was never a sales success but was intended to bridge the gap between the regular DB9 and hotter DBS.

Meanwhile, the DB9’s replacement has already been spotted performance testing at the Nürburgring, two years before its market launch.

The DB11 will be powered by a choice of two engines: a twin-turbocharged version of the existing 5.9-litre V12 and a new twin-turbo 4.0-litre V8 sourced from Mercedes-AMG. In base form, the DB11 should have just over 500bhp.

As well as introducing the DB9 GT, Aston Martin has made changes to the Vantage and Rapide. Vantage models get a new touch-sensitive centre console and the Vantage S and Rapide S get the firm’s Ami II infotainment system. New interior and exterior colour and trim options also feature across the range.

Prices for the MY2016 cars will be announced before the cars go on sale in the third quarter of this year.