Jaguar XKR-S

Jaguar's test facility is gigantic. Covering 2,000 square miles, it borders Snowdonia National Park, which sweeps alongside the rivers and craggy mountainsides of Wales.

These roads are purpose-built for fine-tuning cars. There are cambers, compressions and crests preserved within every road surface ever invented. Throw in unpredictable weather, kamikaze sheep and Jaguar's ace chassis engineer Mike Cross, and you begin to understand why the new 2009 Jaguar XKR-S is so brilliant.

But right now, Cross doesn't want to talk about the Jaguar. He's more interested in the Maserati Gran Turismo S we drove a couple days ago.

"How does it ride?" he asks us.

"What's the gearbox like?"

"The engine?"

Later we discover Jaguar has a Maserati Gran Turismo S on order. The team is clearly taking the Italian competitor very seriously indeed. So how does the XKR-S stack up?

A Rare Jaguar
Limited to just 200 units and available only in Europe, the 2009 Jaguar XKR-S has the Maserati beat in the exclusivity department, although at roughly $111,000 it's significantly less expensive than its $135,000 Italian rival.

The $18,000 premium over the standard XKR adds lightweight forged 20-inch wheels; upgraded brakes from Alcon, a racing specialist; suspension revisions; unique styling tweaks; and interior upgrades borrowed from the earlier Portfolio edition with soft-grain leather and a Bowers & Wilkins stereo.

There are no changes to the supercharged 4.2-liter V8, so it makes the same 420 horsepower and 413 pound-feet of torque as the standard XKR. Jaguar says the XKR-S is capable of zero to 60 mph in just 4.9 seconds, while the car's top speed has been raised from 155 mph to 174 mph.

Not Quicker, but Quick Enough
So the XKR-S is really an XKR equipped with an optional sports pack and while the wheels and aero mods will remain unique, you'll be able to spec the same brakes and suspension upgrades on a regular R.

There's really no need for an engine upgrade in the XKR-S anyway. It's still capable of melting the huge 295/30R20 rear tires with ease. Squeeze the accelerator a little more and the six-speed auto kicks down quickly, intensifying the supercharger's otherwise unobtrusive whine. From there it's a one-dimensional charge to the redline and it feels good every time.

An active exhaust system gives the XKR-S an appropriately rich sound, but it can't quite match the Maserati's more expressive normally aspirated V8. More important, the XKR-S is more than 200 pounds lighter and has more engine torque than its Italian rival. Slingshot out of hairpins and the Jag has an excess of power where the Maserati takes time to gather speed.

A Proper Automatic
Like the engine, the XKR-S's six-speed automatic transmission remains unchanged. It's a good call. The clumsier in-town progress of the Maserati's single-clutch automated manual is at odds with the refinement customers expect. The Jag's torque converter blurs the transitions between gear ratios more effectively and still offers shift paddles (attached to the steering wheel, not fixed on the column), and the smooth gearchanges are still quick enough when the mood takes you.

Unlike the Gran Turismo S, however, a pull on a paddle doesn't lock the XKR-S into manual mode. It will still kick down, still change up at the redline and quickly revert to auto mode if you stop making paddle inputs. It's an automatic, not an automated manual.

Getting Your Money's Worth
If it weren't for the revised suspension and upgraded brakes, the XKR-S would be a far more questionable purchase. New springs, stiffer antiroll bars, retuned dampers and a quicker steering ratio work with a recalibrated version of Jaguar's Computer Active Technology Suspension (CATS) to give the XKR-S its unique feel.

When you turn into a corner, you can feel the weightier steering effort, a by-product of changes to the front suspension's steering geometry. The steering is still fingertip light, but the quicker reactions give clearer feedback from the front end. When you travel over broken tarmac in the Maserati, you find it's pretty unyielding. Yet while the XKR-S is unmistakably stiffer, it remains supple. Wind the car out over these tricky Welsh roads and it becomes sensational. The standard car's slightly lolloping on-limit behavior is gone, as the R-S feels far better tied down over crests and more composed through compressions.

The more robust brake system is a noticeable improvement as well. Up front there are 15.7-inch rotors with six-piston calipers, while the rear end gets 13.8-inch discs with four-piston calipers. As good as the standard car's pedal feels, the XKR-S is even better, with a firmer pedal with a progressive bite and no apparent brake fade.

There's such highly detailed communication from the front end that you stop braking hard into corners and start working the tire grip more aggressively. You feel the weight build on the outside front tire, feel the light smudge of the rubber nudging into very mild understeer, then choose either to back off and ride it out or push through for oversteer.

With all the traction control systems off, you can go as hard as you want without ever questioning what's going on below. This experience bests the Maserati in both intuitive involvement and refinement.

Not Quite the Ultimate Jaguar, but Close
We did notice one obvious flaw: the 2009 Jaguar XKR-S does without a limited-slip differential. Floor it out of a hairpin and one tire bonfires.

Mike Cross points out that this is very rarely an issue on the road. But he also describes the XKR-S as "a road car you can take to the track." And what's the fun of a powerful rear-driver on track without a limited-slip diff?

We suspect that the folks at Jaguar are counting on the fact that those who are willing to fork over the extra cash for the XKR-S won't be too concerned. And they're probably right.

As much fun as this XK is to flog hard, it's the badges, both the growler on the front and the "XKR-S" plate on the back, that'll sell it. Too bad really, as it's one of the most engaging coupes in its class when the road gets twisty. Jaguar has no reason to fear its Maserati rival, because the XKR-S holds its own just fine.