Used 2012 Jaguar XK

We're doing 140 mph and the 2012 Jaguar XKR-S is still pulling hard. This is Portimao, a new circuit in Portugal built to Formula 1 standards. It's quick, varied and undulates dramatically across the landscape. We crest a brow in 5th gear, lean on the huge steel brakes and click down to 3rd for a 90-degree right-hander as the quad exhausts pop and fart.

The steering is lighter than we expected, but the XKR-S responds with a vigor not found in any other Jaguar. The nose pivots, the suspension sets, the 20-inch Pirellis bite and the most powerful road-going Jaguar ever makes a bid for the apex. Feed the power, unload the lock and feel the rear end slither as 550 horses make a bid for freedom. Soon, we're at wide-open throttle again, and the Jaguar XKR-S lets out a guttural roar.

More Than Just Pretty Paint
Sold only as a coupe, the 2012 Jaguar XKR-S builds on the standard XKR in ways you can only begin to appreciate when it's sitting in pit lane: The changes here amount to much more than a porno body kit and lurid French Racing Blue paint.

Jag has loaded up a new fuel map for the supercharged 5.0-liter V8, and this, coupled with the introduction of an active exhaust, delivers increases of 40 hp and 41 pound-feet of torque over the standard XKR. In addition to the 550 horses, the 2012 XKR-S promises 502 lb-ft of torque from 2,500-5,500 rpm. Short of thrust it is not.

There's still a six-speed automatic transmission driving the rear wheels of the Jaguar XKR-S, but it's one of the best automatics in the industry and works well even on the track. Pull the left-hand paddle on the steering wheel and you get quick, rev-matched downshifts. The transmission even skips gears in response to several rapid tugs of the paddle.

Hangs on Like a True Sports Car
Although Jaguar's engineering guru Russ Varney insists we should judge the XKR-S as a "sports GT," rather than a road racer in the mold of the Porsche 911 GT3, he and his team went to work on the XKR's chassis to make it more capable on the track.

A new aluminum steering knuckle allowed the engineers to increase both negative camber and caster up front, so the steering feels more precise and secure when you're changing direction with commitment. Further, the Active Differential Control, which uses wheel speed, yaw and steering angle sensors to modulate torque between the rear wheels, has been reprogrammed to provide greater stability as the XKR-S approaches its claimed 186-mph top speed.

The ride height is 0.39 inch lower on the 2012 Jaguar XKR-S, and spring rates are up 28 percent in front and 32 percent at the rear.

Wider, forged alloy wheels, measuring 20-by-9 inches up front and 20-by-10.5 inches out back, promise better grip while reducing unsprung weight by a total of 10.6 pounds compared to the regular XKR. They're fitted with Pirelli P Zero summer tires, size 255/35ZR20 front and 295/30ZR20 rear.

The Soul of a Muscle Car
Marketing types will tell you that the XKR-S belongs to a genre of car described as "sub-exotic." Like its most obvious rival, the 911 Turbo, Jaguar's coupe is billed as an everyday performance car, not a weekend toy.

But nothing about this Jag feels practical or sensible when you wood the throttle. You breathe in a wisp of tire smoke, watch the nose rise and hear the blown V8 bellow as the car pummels the air in its path. Put crudely, the XKR-S gathers speed like an old-school muscle car. Even with ridiculous blue paint, it's so alpha male it makes the standard XKR look like a metrosexual in a pair of skinny jeans.

Jaguar says the XKR-S hits 60 mph in 4.2 seconds and arrives at 100 mph in 8.7 seconds, and we've little reason to doubt the carmaker's sincerity.

Hey, Guy, Looking for a Challenge?
Chief test driver Mike Cross tells us his team has deliberately engineered the 2012 Jaguar XKR-S to challenge its driver, noting that the standard XK and XKR already cater to meeker souls. Whereas a 911 Turbo feels almost benign, the XKR-S threatens and cajoles in equal measure.

A new track-themed stability control mode allows the car to take attitude — to the point where you instinctively apply opposite lock. On the Portimao circuit, it's a teaching aid. Get brutal with the throttle and you'll get a smack upside the head as it cuts power. Drive smoothly and it lets you edge closer to the limits while providing a useful safety net.

Turn the system off and you have a car with a vast repertoire of skills that demands care and attention. Although the 2012 XKR-S is set up to understeer at the limit, it's comically easy to induce oversteer. If you know what you're doing, it's an absolute hoot, helped by the talkative steering and linear throttle response.

If there's a weak link in the package, it's the brakes. Lacking Porsche's deep pockets, Jaguar has yet to develop carbon-ceramic brakes. The steel set on the XKR-S offers plenty of initial stopping power, but the middle pedal goes soft after just three laps around Portimao. For track-day use, the stock brakes simply won't do.

Away From the Track
Although Jaguar expects most XKR-S owners to take this car to a circuit, this coupe never feels like a track-day special.

On the road, it's remarkably well mannered, as well-tuned adaptive dampers ensure the ride is never harsh or uncomfortable. Surprisingly, the damping actually feels less aggressive than on Jaguar's XFR sedan.

When we turn onto a twisty back road, we also can't help but notice the bulk of the 2012 Jaguar XKR-S. Even with its aluminum unit-body, the XKR-S is still a heavy car at 3,865 pounds (versus the sub-3,500-pound 911 Turbo). It's beautifully balanced on both road and track, but you never quite forget its size. This is a car that's led by its nose.

Making Jaguar Cool Again
There's no denying that the 2012 Jaguar XKR-S causes a stir, even if you opt for something more demure than French Racing Blue.

Design guru Ian Callum argues that the aesthetic changes on the S are driven by a desire to optimize stability at very high speeds. Though the carbon-fiber front splitter and rear wing reportedly reduce lift by 26 percent, their role is also to make a bold statement about Jaguar's future direction. The XKR-S, like the C-X75 supercar, is all about making small boys salivate at the sight of a Jaguar. If 15-year-olds think a Jaguar is cool, says Callum, their dads will, too.

You might just squeeze a kid into the XKR-S's rear seats, but only just. This is really a two-seater with space behind the seats and a capacious trunk. All the controls are laid out sensibly and the sport seats are excellent, but the XK cockpit is starting to feel dated and despite recent improvements, some of the plastics don't feel worthy of a $130K car.

The XKR-S cockpit is identified by appliqués of carbon-look leather, which is starting to feel a bit 1990s. There are "R-S" badges, too, but it's a shame that the gauges have been left unchanged. It'd be nice to have an alternative to the bulbous XK steering wheel, too.

Most Exciting Jag Since the E-Type
Brash and extroverted in all the ways a Porsche is not, the 2012 Jaguar XKR-S is more than just a halo for the face-lifted XK range. It's a statement of Jaguar's newfound confidence. Freed from the shackles of Ford's ownership and the need to protect Aston Martin's market position, the automaker can at last give full expression to its sporting aspirations. The result is the most exciting Jaguar since the E-Type.

There will be those who say that a $35,875 premium over the standard XKR is excessive for a body kit and retune, but the engineering is thorough and the shift in the car's character shouldn't be underestimated. A British bruiser of the old school, but with modern manners, the 2012 Jaguar XKR-S is a wonderful expression of what can be done with engineering talent and the right suits making the decisions.

Edmunds attended a manufacturer-sponsored press event to facilitate this report.