Video: Eagle Low Drag GT review On top of this, Brace has developed hundreds of upgrades to modernise or enhance the E-Type experience, not least Eagle's own version of the straight-six engine, bored out to 4.7 litres and with a cast aluminium block to reduce weight. To that you can add Eagle's own five-speed gearbox and big, modern brakes. And you can do all of this knowing that it has been conceived with the utmost sympathy for Malcolm Sayer's original design. Take the air-conditioning for example, which sits inside a replica of the housing that would have originally held the inner workings of the heater, so when you lift the bonnet you don't even spot it's there. It is such attention to detail that results in that eye-watering price. Still too steep? Well, you could save a few hundred thousand by eschewing the Low Drag GT shape and opting for a "basic" Eagle E-Type, which takes 18 months to build and will set you back just £300,000. But don't think you can hang around for a second-hand one; owners, who include ex-Formula One driver Martin Brundle, simply don't sell their cars. Besides, with only 36 complete Eagles built since the East Sussex-based company turned from a classic car dealer to an E-Type specialist in the early Nineties, the pond from which to fish would give a goldfish claustrophobia. To date, the most special of all its projects has been the Speedster, a two-seater, open E-Type designed by Brace as a kind of ultimate classic car and featuring every conceivable Eagle upgrade. Its appearance on BBC Top Gear as part of the E-Type's 50th anniversary celebrations sent Eagle's reputation soaring. However, Pearman's dream of the ultiamte GT version of an E-Type predates the Speedster. Indeed, Eagle had set about working on such a car a decade ago, and it was only increasing demand for customer cars (at its peak, Eagle had an eight-year waiting list), that meant the project was placed on the back burner until a buyer expressed an interest and the wheels were set in motion. In September, four years and about 6,000 man hours after that buyer commissioned the build, the Low Drag GT was unveiled at St James's Concourse of Elegance, in London, its reflective silver paintwork indicative of the aluminium panels used to form the coupé"s body. Yet while the shape will be familiar to E-Type aficionados, mimicking as it does the trio of low-drag race cars built in the Sixties, this is the only one you'd consider driving anywhere but a track. That's because, as racers, those original E-Types (as well as the replicas built over the proceeding years) are cramped, noisy and completely unsuited for touring. To tackle this, Eagle set about its usual process of building a car. "All Eagle E-Types use original Sixties" Jaguars as the basis. Even for the Low Drag we've taken a pretty rusty old coupé, stripped it right down to its last component and rebuilt it," says Pearman. That includes lowering the floorpan by an inch and a half, as well as adding 2in to the car's length, to increase cabin space. The 16-gallon fuel tank is lower and wider, to allow a bigger boot, and gives a touring range of about 350 miles. Under the long bonnet is the 4.7-litre, aluminium block straight-six complete with Eagle's sequential fuel injection system. It's good for 345bhp and 360lb ft of torque. There's also Eagle's five-speed gearbox and limited-slip differential, both in aluminium. While it retains the original independent wishbone configuration, the Eagle's suspension has had a comprehensive makeover, including adjustable dampers. Climb inside and the only obvious visual difference between an original E-Type and this is a pair of air vents that flank a modern Pioneer stereo. The Smiths dials, patterned aluminium dash and thin, wood-rimmed wheel all whisper of an authenticity that works perfectly with the spotless, unmarked leather seats and glitzy Alcantara roof lining. The only absentee is the patina that comes with a well-used classic. Out on the road, that the biggest challenge presented by the Low Drag is that its steering wheel sits on the left (at the owner's request) speaks volumes of how easy it is to drive. The clutch is heavy but the gearshift smooth, and the steering, which uses speed-sensitive power assistance, is a revelation, as light for parking as a supermini's but brimming with feel once up to speed. And speed, thanks to all that torque and a dry kerb weight of just 1,038kg, is something the Low Drag GT accumulates with ease. Eagle quotes 0-60mph in under 5sec, and a top speed north of 170mph, which both seem eminently feasible given how the car leaps to attention on even part throttle. Body roll is slight and the ride and visibility excellent. And while the AP Racing brakes lack ABS, they are powerful and are easily modulated. And that, I'm afraid to say, is where I lost my road tester's nerve. For as much as I wanted to sprint through the revs, or lean on the 235-section tyres, so the greasy roads and that figure of £650,000 nagged at me like a toddler wanting a new toy. So I'll leave it to other publications to detail how beautifully balanced the Low Drag GT feels at the point where the rear relinquishes grip, and simply tell you that in terms of concept and engineering this is the most impressive car I've ever driven. Anyway, I'd wager the satisfaction of driving this incredible machine at the limit pales into insignificance against its ultimate thrill. That being, of course, the moment you come to a gentle stop, switch off the engine and hand it back in one piece. Eagle Low Drag GT Tested: 4.7-litre six-cylinder petrol engine, five-speed manual gearbox, rear-wheel drive Price/on sale: Approx £650,000/now Power/torque: 345bhp @ 4,800rpm/360lb ft @ 3,600rpm Top speed: 170mph+ Acceleration: 0-60mph in under 5sec Verdict: Made in Britain and about as polished an update of a classic car as you'll find anywhere in the world