We've lauded the aluminum-structured and dressed XK in previous reviews, and it was with great anticipation we flogged the amped-up R version through the south of France (forget, by the way, any talk of champagne, chateaus, or political disagreements--this country is brimming with miles upon miles of great driving roads). The R is available as a coupe and convertible, and we drove both among fields of waving wheat, brilliant sunflowers, and rolling vineyards.
The transformation from standard to R spec is straightforward, and chief engineer Mike Cross summarizes it succinctly. "Working with [the naturally aspirated model] as our base, our brief was to create 'XK plus 30 percent'--the ultimate sports GT for the real world." The 4.2-liter V-8 gets a supercharger and intercooler (something Jaguar has been at since 1995) that cranks up the heat from 300 to 420 horsepower; variable cam timing on the intake side is new as well. This may not sound like much compared with the 500-horse BMW M6, but it's torque that moves the car, and the Jag packs plenty with 413 pound-feet at 4000 revs. The M6, to continue the example, has 383 pound-feet, although the BMW remains the faster machine.
The only transmission offered or needed is the superb ZF six-speed automatic employed by many upscale Europeans. It allows you the choice of standard drive, Sport drive (higher shift points, more driver adaptation), or full manual control via paddle shifters done Ferrari style: Tug the right paddle for upshifts, the left for down. The aforementioned quad-tipped exhaust is of the active variety, meaning that baffles adjust the burble between quiet for cruising and muscular under hard accel. Front spring rates are up 38 percent, while the rears are 24 percent stiffer. The steering is firmed up for more weight and quicker response. The Computer Active Technology Suspension (or CATS--cute) damping system is recalibrated for firmer body control. There's but one minor change to the structure, the addition of a rear-shock tower strut brace.
Nineteen-inch Jupiter alloys are standard, with lovely 20-inch Cremona wheels optional. More go demands more whoa, so the R gets badged calipers and the front rotor size increases from 12.8 to 14.0 inches. Visual upgrades are subtle: all-mesh grillework up front in a revised fascia, functional hood vents that proclaim "Supercharged," aluminum-finished side vents, some badging. The interior gets more supportive sport seats, and much of the logically designed IP is faced in a terrific-looking, latticed aluminum trim. For those who prefer "timber" to "ally," lustrous walnut fascias are a no-cost option.
The previous XK got floaty in the nether regions of the speedo, but this one's stable right up to top speed. It doesn't yet match the autobahn-bred magic of an SL AMG, but it's well-planted and inspires confidence at 120-plus. Initial turn-in is good, if not Porschelike, and the front end bites and stays true. The XKs overall handling persona is neutral; transition to understeer comes at high limits, is gentle, and gives you warning. The stability-control system isn't fully defeatable but, in its most aggressive setting, allows a bit of fun and isn't overly intrusive when it needs to bleed speed. Nice job on the suspension calibrations and damping; a smart balance between response and comfort, and it does a great job soaking up mid-corner bumps. The brakes feel up to task.
Jaguar boasts about the platform's structural stiffness--with good reason. The coupe is ingot solid; just try to make it shake, squeak, or rattle. You need to seek out a nasty stretch to get a wiggle out of the convertible, and even then, any chassis shudder is quelled quickly. Why no retractable hardtop? "Oh, we investigated it and could have done it," says hot rod-loving design boss Ian Callum. "But the look would've been all wrong. In order to make all the panels fit and fold, the top would lose that sleek look, like on an E-Type roadster, or a chopped, padded top on a '32 Ford hot rod. It wasn't an issue of cost or technology. It just wouldn't have looked like a Jaguar any more." The thickly padded, one-touch top looks great up or down, and normal conversation is easy up to about 90 mph.
There are few nits to pick. In spite of all the horsepower justification, the XKR still deserves more like 450, as the range for this class of car runs from the Cadillac XLR-v's 443 to the above noted BMW M6's 500. The Jag chassis is so good, it could use even 25-to-30 more horses. But the current V-8 design can't be easily stretched past 4.4 liters, and cranking in more boost to get the power would compromise driveability and durability. A few onlookers felt the front-end design "grilley," although this sentiment wasn't universal. A critical driver touch point--the paddle shifters--feel like cheap plastic bits. Aluminum or leather/suede-trimmed paddles would feel much nicer to the touch. And even 10 percent more steering feel (not weight) would be welcome. The "Plus-2" rear seating? Consider it more like "Plus 0.2."
