First drive: Aston Martin Callum Vanquish 25 by R-Reforged

The 5.9-litre Aston V12 engine gets light modifications (as well as a superb set of specially machined air intake stacks for beauty reasons) so that it now produces 580bhp – an extra 60bhp. Buyers can opt for a six-speed manual or conventional eight-speed automatic gearbox, or stick with the original car’s six-speed automated manual. Despite the bad publicity, some prefer that.

Underneath, as a result of 20,000 miles of extensive testing, the car’s suspension has been rebushed and retuned with new springs, anti-roll bars and Bilstein dampers so that it rides 10mm lower and gets the best performance from Donfrancesco’s preferred Michelin Pilot Sport tyres. Even the steering wheel is stripped and machined to give a rim shape that Callum feels is more appropriate, and to reduce the diameter slightly, before being retrimmed.

Such painstaking work isn’t cheap: buyers will pay around £450,000 if they bring their own car, preferably a Vanquish S (worth around £100,000). Alternatively, the team will find a suitable car on the market. The 25-strong batch is already half sold, even before most prospects have even seen a complete car, boding well for a successful completion.

We spent two hours in Callum’s test car, a six-speed manual. The interior’s architecture is easily recognisable, but every surface gets a quality boost and a large range of textures and colours is now available. The seats are completely redesigned and mounted lower – something the original car badly needed. One fascinating feature is the tasteful use of what’s dubbed ‘Callum abstract tartan’ – a theme likely to be used in future creations. There’s a removable Bremont pocket watch mounted on the dashboard, too, and a custom Mulberry luggage set for the boot.

As soon as you start to drive, it’s apparent the car has near-bottomless reserves of torque and power. Its V12 sounds quite different from that of the original Vanquish, courtesy of a re-engineered exhaust system that emits four distinct but harmonising sounds at once: treble and bass lines, a classic rustle from the valve gear and a faint, refined whine from the camshaft drive system. Also, a new exhaust box forms part of the large and effective underbody diffuser.

Callum and Donfrancesco say the idea is to enhance the grand touring capabilities and driving quality of the Vanquish, and that’s most definitely what they’ve achieved. The engine isn’t obtrusive until it’s really pulling (which it can rarely do on a public road) and always sounds wonderful.

The car rides flat and firm and has much better turn-in and grip than before, thanks to its modern hardware. It stops beautifully, too, using Aston’s latest-specification – and large – carbon-ceramic brakes.

However, two things really stand out for me from the dynamic package. One is the new excellence of the steering, whose impressive precision and deliberate effort levels are now far more appropriate and deliver a whole new level of sophistication. The upshot is a much more directionally stable car.

The other is the ride quality: flat, controlled and beautifully damped, accompanied by a refreshing lack of tyre noise, because so much work has been done to suppress the original obtrusive road roar. In all, the twin aims of enhancing driver reward and grand touring ability have both been impressively achieved.