When driving 168 m.p.h., you are traveling 250 feet every second. Which means that if you rip past the cluster of sideline photographers at the "five"—the marker indicating that you have 5,000 feet of cleared U.S. Naval Air Facility runway left—and miss the jet mechanic waving the checkered flag at the "four," you have about a count of three before you, and your passenger, and the $133,500 French Racing Blue 2012 Jaguar XKR-S you're piloting, will find it impossible to stop before the tarmac gives way to a baked-mud trench, a pile of hay bales, a stretch of the Sonoran desert, and a five-pin arrangement of the Blue Angels stunt planes that are based here at N.A.F. El Centro.
Unfortunately, the runway's arresting gear has been removed for this exercise. Also unfortunate, the Jaguar's posh cabin is tranquil enough at this potentially terminal velocity for you to hear your passenger not breathing.
Fortunately, a reminiscence of your instructional briefing dawns as you approach the "three," you stomp on the XKR-S's upgraded (though not carbon-ceramic) brakes, and quickly shed velocity, slowing enough to hang a sweeping right off Runway Bravo without pegging the baby-faced sailor flagging your unintended apex. Mission accomplished?
Between here and Coronado, Calif., — an exclusive oceanfront spit that juts up like the middle finger on America's lower left-hand corner — is 117 miles of highly variant geology that looks alternately like: the Iowa plains, Mars, a Cyclops sandbox stocked with enormous rough-hewn brown-sugar cubes, and someplace you'd see Yul Brynner starting a chariot race. The most thermodynamically efficient course through this terrain is not achieved by redlining the Jag's supercharged V-8 in second gear. But we're devoutly felonious when it comes to the laws of physics. (Can joy be measured in joules?) Encouraging our assault is the car's Sport Dynamic mode, in which the XKR-S sails through the twisties with lithe precision, powers out via copious reserves, and trumpets delightfully from its less-restrictive exhaust, making this, the brand's fastest car ever, one howling wolf of a big cat. (Note: auditory benefits are greatly enhanced in the convertible.)
Jaguars have long trodden the borders between sporting and luxurious, with two wheels fully gyrating in each segment. The "base" XK tends to lean lavish: a capable GT condemned to ferrying its owners toward golf, or cosmetic surgery. The R-S grinds gloriously toward the racy. Externally, this makes itself known via a rather carbuncular collection of scoops and foils, and a fender-filling hand and glove upgrade. Internally, it appears as a flawlessly ubiquitous leather sheathing, even on the headliner (which, in matte charcoal, resembles the night sky on your ideal vacation.) Under-hood, it receives a super-supercharger that piles bark upon bite (mewl upon scratch?) resulting in enough additional agency to hit a boggling 550hp and 502 lb-ft. All this, plus stiffer springs, firmer knuckles, a lower ride, and a magic differential translate into low 4-second times to 60 mph, high 180-mph up top, and sub-8-minute orbits around the Nürburgring.
In our mixed driving — coursing around mountains, blasting across Interstates (and jetways), side-winding through deserts, and shrieking indecorously through the more decorous parts of Coronado — the XKR-S performed admirably, meaning: it drew copious attention, it produced cacophonous noises (both out back, and via the 525-watt Bowers & Wilkins stereo), and it made every thrilling effort to run over its front wheels with its rear ones.
Is it dynamically rewarding? Hell yeah. Does it cosset you in unrelenting luxury? Comme il faut -- although we still hate its cumbersome infotainment interface. Is it competitive with heroic coupes/convertibles in its category? Imagine the pertinacious poise of a BMW M6, crossed with the supple shriek of a Maserati GT, and add a soupçon of the Porsche 911 Turbo's buttoned-up brutality. With the American allotment of 100 open and 100 closed cars sold out for 2012, act fast if you want in on this elite club for 2013. Just don't forget to watch for the checkered flag.
Brett Berk's automotive writing has appeared in Businessweek, Car and Driver, Esquire, GQ.com, Jalopnik, The L.A. Times, and in Vanity Fair where he writes a weekly online car column, and covers the category for the magazine. Visit him at brettberk.com or follow him @StickShift_VF.