The XKR's newly invigorated engine is Jaguar's AJ V-8, a 4.0-liter engine that in naturally aspirated form makes 290 horsepower. With the addition of the supercharger, it surges to 370 horsepower. It's very similar to the supercharged powerplant in the XJR sedan, but to fit under the XKR's sloping hood, some minor modifications to the intercoolers and cooling system were made.Jaguar says it chose supercharging over turbocharging for its immediate throttle response and superior torque at low revs. When prodded, the XKR responds with breathtaking acceleration. Yet it can crawl through miles of snarled traffic without raising a claw - or the temperature gauge. The supercharged V8 develops 387 foot-pounds of torque, fully available from just 3600 rpm, which provides the XKR with effortless response to throttle movement. At just 1600 rpm, the supercharged engine is already producing more torque than the XK8's naturally aspirated V8 generates at its peak. Purists should no longer be shocked to learn that Jaguar uses a five-speed automatic transmission built by Mercedes-Benz. (Perhaps the car world would be a better place if we all just used GM or Benz automatics and Nissan and Honda manuals.) What we all want from Jaguars are stunning looks and breathtaking speed. Fortunately, the XKR delivers those in abundance. It accelerates from 0 to 60 mph in about 5.2 seconds (a tick more for the slightly heavier convertible) and charges to an electronically limited top speed of 155 mph. It bears noting that Jaguar clocks the XKR as being faster than the Porsche 911 or Mercedes-Benz SL500. XKR's suspension and tires put all of its power to the ground in a delightful manner. Its suspension consists of control arms and shocks in front and a hallmark quasi-independent rear suspension that uses the driveshafts along with control arms and coils as suspension components. In addition, the XKR features a Computer Active Technology Suspension (or CATS) that harnesses computer-processing power to change shock settings. The blend of a comfortably firm ride and responsive handling is appealing. While road impacts can be felt slightly, the sum of its responses makes it a cozy vehicle for long highway jaunts and for assaulting your favorite sharp corners. Its variable-ratio power steering is exceptionally sharp without wander and abrupt kickback. Massive 18-inch Pirelli P Zero tires (245/45ZR18 in front, 255/45ZR18 in back) provide an amazing amount of grip that inspires driver confidence. Dynamic differences between the coupe and convertible are minor. The coupe has a rocklike solidity that previous experiences in 1980s-vintage Jaguars made seemingly impossible. The convertible shudders a bit over the largest road crevasses, but not improperly. The convertible's cloth-lined top seals well against wind noise. It's an attractive soft top, among the few convertible tops that fits that description.
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