The Eaton-blown engine sounds much better than the whiney one in the old XKR

In a parallel universe, it's easy to imagine Jaguar and Aston Martin going head-to-head with the XKR and DB9. Talk to the men behind the new XKR and, although none of them actually comes out and says it directly, you know they'd relish the opportunity to roll up their sleeves and have a round of fisticuffs. Instead, joint Ford parentage means Jaguar has to assume the role of subordinate sibling. While Aston Martin gets a charismatic boss, a shiny new factory, a well-funded GT race programme and a starring role alongside 007, Jaguar is charged with clawing back lost ground in a sector it arguably should never have been in, with long-overdue diesel variants of stodgily-styled saloons.

Perhaps that's why, with the XKR, there's a real sense that the men at Jaguar have grasped this as a golden opportunity to remind everyone what this big cat is really about. The company line has it that the XKR competes with cars like the Mercedes SL500, BMW 650 Ci and Maserati GranSport. It also acknowledges there's some crossover with the Porsche 911. What it doesn't include is the Aston Martin DB9. However, assuming that the old racer's adage about a team-mate being the one to beat holds true with engineers, Jaguar's dedicated and enthusiastic team wouldn't worry if they gave the guys at Aston a few sleepless nights.

They've certainly assembled some promising ingredients: a reworked, supercharged driver-oriented paddle-shift six-speed automatic transmission and slotted into the XK's light, stiff aluminium chassis makes for the fastest and most focused Jaguar in decades.

The styling is by Ian Callum, and while it's easy to criticise the former Aston Martin designer for staying well within his comfort zone, when you've developed a knack of combining curves and proportions to such satisfying effect, you can't blame him for not fixing what isn't broke. Besides, if the reaction of the Dubai public is anything to go by, his pen is still filled with magic. Everywhere we go the XKR draws huge attention, particularly from females.

That's not to say it's perfect. Details grate, such as the telescopic electric aerial, which, even when retracted sits like a zit on the XKR's otherwise peachy behind; the rear tail lights that sit level with the boot on one side, but not on the other. The bonnet louvres, with the moulded-in legend 'Supercharged', look effective from a distance but cheap close-up, and the nose, now peppered with bright aluminium-finish grilles, is incongruously square-jawed. Adventurous it's not, but judged as a whole the XKR is muscular, striking and unmistakably Jaguar. Most importantly, it's a car you want to drive. And it drives well.

Which is just as well, as we're due to drive it across the length and breadth of the United Arab Emirates. It's the perfect test for what Jaguar promises is a consummate GT: endless two-lane highways to assess its refinement and mile-eating ability, followed by some of the finest driver's roads in the Middle East to stretch its chassis and powertrain to the limit.

Open the door and first impressions are OK. It's fresh and modern, but we're not big fans of the two-tone aluminium - it looks cheap - rather than wood that covers the dash, although you can still specify veneer if you prefer. There are nice touches: the embossed 'R' logos that adorn the leather head restraints and the keyless ignition. You don't twist the key, rather you keep it in your pocket or stow it in the centre console, which, incidentally, we found a little clumsy and annoying. Too many times we were left struggling to get the key out of its holder. To start the car, you simply depress the brake pedal and finger the obligatory starter button. The V8 catches with an encouraging grunt - less strident than an Aston, but pleasingly vocal by Jag standards - before settling into a hushed, smooth idle.

You don't expect to find paddles behind a Jaguar steering wheel, which may account for why you're happy to slide the selector into 'D' and drive. Even in this mildest of modes there's plenty of silky urge on tap, and the upshifts are slick and punchy. Compared with the slightly lazy demeanour of the old XKR, this is an encouraging start.

It's always been vital to Jaguar, and chief engineer Mike Cross in particular, that the XKR is taut enough to cope with the extra performance on offer but supple enough to retain a mature balance of ride and handling. Using the latest iteration of Computer Active Technology Suspension (CATS), the XKR's springs and dampers have been stiffened accordingly, but as we pick our way through the traffic in Sharjah and out onto the highway, it's clear the XKR also retains Jaguar's trademark pliancy.

The aluminium structure is clearly a big help. A whopping 70kg lighter than the old car in coupe form (100kg for the Convertible), the new XKR is also much more rigid. To give you some idea of just how much, the new XKR Convertible is stiffer than the old XKR coupe, which has given Cross and his team more scope to hone the chassis. Also, with more power and torque to play with, and less mass to haul around, it's no wonder the XKR is a much sharper and more alert machine.

'Our brief was to create XK plus 30 per cent,' explains Cross. He exceeded his target, for thanks to the lightweight construction and the powerboosting benefits of twin air inlets and Variable Inlet Camshaft Timing (VICT) the XKR is actually 'XK plus 34 per cent' in terms of power-to-weight ratio. That equates to serious performance, the 1665kg coupe hitting 100kmh from a standstill in a claimed 4.9sec.

Right now, raw pace isn't in demand. We've got an hours drive ahead of us, all of it on the highway. With little to no traffic and 420bhp at our disposal, it's hugely tempting to wind the Jag up to 250kmh, but with the road punctuated by radars almost every kilometre, we sit at a leisurely 120kmh and risk dropping off to sleep.

Our reward for such self-control comes later that same day, we are now up in the Hajjar mountains. We make for the delights of the stretch between Hatta and Kalba, revelling in the prospect of its fast, inviting sweeps, majestic climbs and sinuous descents. After a typically impressive display of smooth, refined highway work, this is where we can discover whether this comfortable loafer conceals a set
of running spikes.

It's great to be able to reach for those chunky paddles and take control of the transmission, for doing so marks the transition from relaxed progress to attacking driving. The sense of control increases ten-fold; the urge to accelerate harder and longer down the straights and brake harder and deeper into the corners intensifies to a level way beyond anything the old XKR could inspire or deliver. Crisp, snappy upshifts perpetuate the sense of seamless, spirited propulsion, while punchy, immediate downshifts, complete with perfect stabs of virtual heel-and-toe throttle, add finesse and stimulation in equal measure. The downside is the brakes don't have much power and are too small compared to other sports cars and, say, the S8, which is tested elsewhere in this issue. The pedal isn't quite as feelsome or as firm as you'd like.

Worked hard, the Eaton-blown V8 sounds so much better than the whiney old engine. Jaguar claims that the supercharger noise has been reduced by 5dB, and in place of the strained note of the old motor the new XKR emits just enough of a scream from the supercharger to know it's there, but never enough to overwhelm the more satisfying, cultured V8 note.

The steering is light by sporting standards but weightier than Jags of yore, and though you sense the feedback is finely filtered before it reaches the rim of the steering wheel, there's enough to feel the XKR working its tyres into the tarmac. Consistency is its forte, reacting with the same measured response through fast and slow corners alike. You feel calm and confident, reassured by the chassis' grippy neutrality and eventually informed of the approaching limit by the soft-edged push of gentle understeer.

True to Jaguar's brief, the XKR is a car to flow with, not fight, and while this means it lacks the edge and challenge you get from, say, a 911 (or indeed a DB9) that doesn't mean it wants for point-to-point pace. As Mike Cross isn't averse to viewing corners through the side windows, it's also safe to say that the XKR will wag its tail on demand, although sadly we couldn't discover this for ourselves, because we couldn't switch the stability control system off on our car.
It's a shame, for although the XKR is extremely driveable with the system engaged, it would have been useful to feel how this lighter, firmer and more agile Jaguar responds to a more aggressive driving style. The lack of a limited-slip diff suggests it won't deliver the edgier experience some of us would like but, to be fair to Jaguar, that doubtless makes it more suited to its core customer.

That's not to say that the XKR is soft, for perhaps Jaguar's biggest achievement is that despite staying true to the original XKR's loyal and sizeable customer base with predictable, fluid handling and readily available performance, the new car is significantly sharper and more involving. The engine has memorable power, tremendous flexibility and real character, while the six-speed automatic gearbox sets a new industry standard by combining tremendous refinement and smoothness with precise control and immediate response

At c$ 100,000, the XKR is keenly priced. With invigorating dynamics, enduring class and genuine desirability, it's surely destined for desperately needed, and well-deserved, success. Jaguar's engineers have made their point.

Copy Cat
If the assertive and muscular lines of the Jaguar XKR look familiar, it's because they are. They were designed by Ian Callum, once of TWR and the man responsible for creating the Aston Martin DB7; a car for which he was awarded the Jim Clark Memorial Award in 1995 in recognition of his styling work.

Though Callum juggled his jobs at both Aston Martin and Jaguar for a period, his influence on the DB9, the successor to the DB7, is often disputed (it was finished by Henrik Fisker), but there is no doubting that both this new XK and the DB9 are a nod to the most successful Aston Martin of all time.

The front-wing power vents, the distinctive oval grille and prominent bonnet power-bulge are all elements lifted from the design of the DB7. Details like the sweeping front and rear light shapes and powerful stance are also evident in all three cars. And they have certainly catapulted Jaguar sports car design firmly into the modern era. Recent Jags have tended to stick close to the tried and tested formula of the past, but, with the XK, Callum has been keen to demonstrate that it doesn't have to be that way.

'It looks just like a Jaguar should - powerful and exciting,' says Callum. 'That power comes from a sense of tension, muscle and form and is very much part of the new design language.'

That new language begins with the proportions and stance, which are dramatically different from those of the previous XK. The new car sits on a longer wheelbase but it has markedly shorter overhangs. Similar to DB9 and DB7 before that, the XK has a strong, high waistline and short, powerful haunches. With its dynamic bonnet and roof lines it looks much more compact and more contemporary than previous models of the same car. Put next to the DB9, with initial glances, it's hard to tell them apart. Callum's influence is clear.

'I am very proud of the new XK,' adds the Scottish-born director of design. 'It is contemporary with wonderful modern proportions yet we have succeeded in integrating design cues from our heritage. The front grille, for example, is pure E-type, and makes the perfect statement that this is, first and foremost, a Jaguar.'

Thanks to Exotic Cars (+971 4 3384339) for the loan of the Aston Martin DB9