The more aggressive XKR-S builds on the standard XK's lines with a more aggressive front end and aerodynamic elements, deep hood vents, and, of course, R-S badges. To my eye this cat looks a bit like a catfish from this angle, but in person the Ultimate Black XKR-S looks just sinister.
The most important upgrade to the XKR-S' spec sheet is the 550-horsepower supercharged V-8 engine. That's 165-ponies more than the standard XK and 40-ponies more than the XKR. This makes the XKR-S the most powerful production model that Jaguar has ever sold.
In addition to the increased power, the XKR-S features a lower stance, lightweight suspension components, and revised rear suspension geometry that provides fantastic grip. It's remarkably difficult to get the R-S out of sorts, even with 502 pound-feet of torque on tap.
The XKR-S' 20-inch wheels house 15.75-inch brake rotors with double-piston calipers on the front end and 13.8-inch disks out back with single-piston stoppers. Like most bits present on the R-S, these are the most powerful brakes ever fit to a Jaguar.
Power exits through the rear wheels, but not before being distributed by a system that Jaguar calls Active Differential Control. This clutch-based rear differential operates like a traditional open differential to provide efficiency and reduced gear noise under most driving conditions. However, when it senses that you want to have fun, it can actively send power across the axle to provide "controllable power-on oversteer."
If you like a bit of raucousness to go with your British refinement, then this is where the magic happens. The XKR-S purrs through quad exhaust tips peaking from beneath the carbon fiber rear diffuser, creating a fantastic rumble at idle. Put the accelerator into the carpet and the exhaust note springs to life with a decidedly muscle car roar.
The XKR-S makes use of carbon fiber extensively in its new aerodynamic additions, counting the new decklid spoiler, rear diffuser, and front splitter among the parts molded from the lightweight material.
The sport seats have cutouts to accommodate a racing harness, should you decided to track your XKR-S. Our tester's buckets were shod in two tone leather, but the seats are also available sans-upholstery with exposed carbon fiber.
The Jaguar's cabin is a classy space. With the exception of the glossy plastic center console, which I find rather chintzy, nearly every surface of the cabin is covered in leather, fabric, or metal. Even the headliner is shod in leather!
The Jaguar's large steering wheel gives away its grand touring roots, but the thick rim feels good in the hand--particularly with their integrated heating elements keeping the digits warm on a cold, rainy day.
Instrumentation is basic and decidedly retro, however a color LCD integrated between the dual gauges can be used to display vehicle info, trip computer data, or turn-by-turn directions from the navigation system.
A single-option six-speed automatic transmission converts torque from the engine into power at the wheels. The gearbox makes use of the goofy drive selector knob that debuted on the XF, but gives users the option to manually chose ratios with paddle shifters.
These rubber volume and skip rollers were a bit odd to use at first, but ultimately fall nicely into the hand and added a nice luxury feel to a control point that would normally consist of plastic buttons.
The Jaguar's cabin is as quiet as a tomb, so the stereo doesn't have to work too hard to overcome road and engine noise. Fortunately, that didn't stop Bowers and Wilkins from over-delivering with an audiophile-worthy premium audio system.
Jaguar's infotainment system still leaves much to be desired where user friendliness is concerned. Jumping between the different function screens (audio controls and climate controls, for example) requires a slow, animated trip back to the home screen before you can get where you're going.
The interface itself is easy enough to understand, with large buttons and bright colors, but I can't help but to think that too much emphasis is placed on the touchscreen. Seat and steering wheel heaters, for example, should probably be physical controls.
Bluetooth handsfree calling is standard on the XKR-S, but audio streaming is not available. This omission, along with the lack of an auxiliary analog audio input, means that it's nigh impossible to use a non-iPhone smartphone to play music in the Jag.
The XKR-S' navigation is fairly rudimentary by CNET standards. It'll get you where you're going and features traffic data, but it seems dated next to more responsive and glossier systems from BMW, Audi, and Infiniti.
A host of other vehicle options are accessible via the Jaguar's 7-inch touchscreen. When the vehicle's gearbox is placed in Reverse, this screen is also where you'll find the display for the standard rearview camera.