The new six-speed automatic with manual control, a Sport mode, and shifter paddles on the steering wheel, is about three levels of sportiness better than the outgoing transmission and the old, dreaded J-gate shifter. The new twin-clutch transmission allows extremely quick, positive shifts between gears, with little or no lurching on upshifts and a nice, growly throttle blip on downshifts. This is an improvement on the similar ZF transmission Ford uses in the Aston Martin DB9, now with better hardware and software. It can sense aggressive driving and adapt accordingly, limiting upshifts in long corners in Sport mode, and giving instant multiple downshifts when conditions are right.

The engine/transmission combination is good for about 5.9-second 0-60 times and 14.4-second quarter-mile sprints, according to Jaguar, with an electronic speed limit of 155 mph. Interpolated European fuel numbers are comparable to EPA numbers of 16 miles per gallon city, and 25 miles per gallon highway, thus no gas-guzzler tax to be paid.

Hugely stiffer than the outgoing car on the basis of its riveted and bonded aluminum construction, almost 50 percent stiffer in bending and much stiffer in torsion, the XK offers the kind of silky smooth ride and demonic cornering that great sports cars have always had. It's helped by the completely retuned CATS adaptive suspension system with faster-acting, smarter shock absorbers that work with the engine and transmission to immediately react to the situation and driver's intention. The tuning is roughly 10 percent stiffer in the front and 4 percent stiffer in the rear than the old car. There are several assist modes to the CATS system, including completely off, for track days.

Another byproduct of the stiff chassis is the steering accuracy. It's without question the tightest, heftiest, and quickest Jaguar power steering in history, but nowhere near the point of skittishness. Solid, stable, and planted. The traction control system now features a Trac mode that keeps everything on but allows a higher threshold of yaw, letting the car get sideways in corners for those owners who go to Jaguar Club track days.

The new XK models are fitted with a choice of 18-, 19-, or 20-inch wheels and tires. Base tires are Continental P245/45ZR18s front and P275/40ZR18s rear. Optional Dunlop SP Sport 01 asymmetric high-performance tires are fitted on XK models with 19-inch wheels, 245/40ZR-19 tires on the front and 275/35R19s on the rear. Optional Dunlop SP Sport Maxx ultra-performance tires are 255/35ZR20s for the front and 285/30ZR20s for the rear.

The XK's new ABS brakes are much larger than those on the previous model, and much more powerful, considering the reduced weight of the car, with braking starting at the very top of pedal travel, where we like it. No fade whatsoever after a long downhill switchback workout.

Although the weights and balances between the coupe and the convertible versions, which we drove back-to-back, are close, there's really no discernable difference in the way they drive, except that the convertible with the top down generates more sound in the cockpit and more admiring glances from the other drivers than the coupe.