ONE FAST Feline; Jaguar's XKR.(News)

Byline: NATALIE NEFF

If the 300-horse Jaguar XK isn't compelling enough to make a cat person out of you, Coventry is set to pounce on the market with its 2007 XKR.

The supercharged 4.2-liter V8 under the XKR's hood features twin air intakes and continuously variable valve timing-mated to what Jag claims is a "class-leading'' six-speed automatic paddle-shift transmission-and cranks out 120 more horses than the normally aspirated version driving the standard XK, with an added 113 lb-ft of torque on tap. Jaguar claims it's enough power to help propel the XKR coupe from 0 to 60 mph in only 4.9 seconds, just slightly longer (5.0 seconds) for the convertible.

Of course, the car's aluminum monocoque construction and light (relatively speaking) weight contribute to its scoot. Weighing 3671 pounds at the curb, the coupe is lighter by 154 pounds than its predecessor, with the convertible likewise slashing 220 pounds. That translates to a 12 percent better power-to-weight ratio than the last XKR, according to Jaguar, and a significant 34 percent better ratio when pitted against a non-R XK.

Expect the big cat to handle the tarmac better as well, given the attention Jaguar engineers directed at chassis and suspension upgrades. The front suspension gets 38 percent stiffer spring rates than the XK, with the rears benefiting from 24 percent higher rates, while an additional suspension brace is mounted between the rear shock towers. Both the Computer Active Technology Suspension (Jaguar terminology for its adaptive damping system, conveniently shortened to CATS) and the stability and traction control systems are recalibrated to account for these changes.

Compared to the previous steel-bodied XKR, the 2007 ...