When it comes to luxury sport coupes and convertibles, the 2012 Jaguar XK gets just about everything right. It starts with the exterior. The XK may not be as adventurous as its newer XF and XJ Jaguar siblings, but its sleek silhouette is often compared to the Aston Martin DB9 (never a bad thing). Inside, the XK isn't quite as grand as the newer Jags, but there's no denying the quality of leather, veneers and other materials that make up its cabin. This year the XK has also been updated with Jag's new rotary shift knob and the latest electronics features.

Those are just aesthetics, however. Under the skin are a finely tuned suspension and a rigid aluminum structure that provides excellent handling and a refined ride. All this aluminum also minimizes weight so the 5.0-liter V8 engine can do its best, whether it's the potent 385-horsepower version in the XK or the effortlessly explosive 510-hp version in the XKR. In R form, the XK hits 60 mph in just 4.6 seconds.

For 2012, Jaguar even turns the dial up a few more notches with the range-topping XKR-S coupe and convertible. To create a dedicated, high-performance sport coupe, Jaguar has bumped up the output of the supercharged V8 to 550 hp, retuned the suspension and added a rather aggressive-looking aerodynamic body kit that includes several pieces fashioned out of carbon fiber. It's a different sort of beast to be sure (especially with its firmer ride), but the XKR-S shows Jaguar can hang with the big boys on the track as well as on the boulevard.

It shouldn't be hard to tell that we're quite fond of the 2012 Jaguar XK. Of course, we're also quite fond of the cars it competes with. The iconic Porsche 911 is also a keen choice, though it's typically more expensive than the XK when options are added. Consideration could also be given to the Mercedes SL-Class, although it only accommodates two and commands a considerably higher sum. Closer in price are the fully redesigned BMW 6 Series and the Mercedes-Benz E550 coupe and cabriolet, although the Jag is far more sporting and lithe than either.

Essentially, there's no way to lose with these cars. But if sleek styling, balanced performance and a reasonable price are priorities, the Jag XK is a great choice.

The 2012 Jaguar XK is available in three models: XK, XKR and XKR-S. Each can be had in coupe or convertible body styles.

The base XK comes loaded with 19-inch wheels, an adjustable suspension, keyless ignition/entry, automatic bi-xenon headlamps, LED running lamps, rear foglamps, power-folding and auto-dimming mirrors, front and rear parking sensors, a rearview camera and automatic wipers. Interior features include leather upholstery and interior trim, heated and cooled 10-way power front seats (with adjustable bolsters and lumbar support), heated power tilt-and-telescoping steering wheel, driver and passenger memory functions, and automatic dual-zone climate control. Electronic features include a touchscreen interface, a navigation system, Bluetooth, a Bowers & Wilkins sound system, a six-CD changer, an iPod/USB audio interface and satellite radio. The convertible adds a power-operated roof and tonneau cover. Adaptive headlights and HD radio are options.

The XKR adds a supercharged engine, different 19-inch wheels, upgraded brakes, upgraded exhaust, adaptive headlights and HD radio. The Dynamic Pack adds 20-inch wheels, revised suspension (springs, dampers, lower ride height), a larger rear wing, a lower front aero splitter, rocker sill extension, a rear aero diffuser and red brake calipers. The Black Pack adds different 20-inch wheels, a larger rear spoiler, front aero splitter and black trim in lieu of chrome. Also optional are adaptive cruise control and sport seats.

The XKR-S adds a more powerful supercharged engine, wider 20-inch wheels in a matte grey finish, upgraded exhaust, a more aggressively tuned suspension, a carbon-fiber front aero splitter and rear aero diffuser, a trunk-mounted wing, an extensive aerodynamic body kit, heated-only sport seats (cooled function removed) and unique interior trim. The Bright Pack adds chrome exterior trim and bright polished wheels.

Options on all XK models include a heated windshield and a sport steering wheel wrapped in faux suede.

The 2012 Jaguar XK is powered by a 5.0-liter V8 that produces 385 hp and 380 pound-feet of torque. As with every XK, rear-wheel drive and a six-speed automatic are standard. EPA-estimated fuel economy is 16 mpg city/24 mpg highway and 19 mpg combined. The convertible achieves 16/22/18.

The 2012 Jaguar XKR gets a supercharged version of the same engine, bringing output up to 510 hp and 461 lb-ft of torque. In Edmunds performance testing, an XKR convertible went from zero to 60 mph in a very rapid 4.5 seconds (the lighter coupe would be even quicker). EPA-estimated fuel economy is 15/22/17 regardless of body style.

The 2012 Jaguar XKR-S gets a more powerful version of the supercharged 5.0-liter good for 550 hp and 502 lb-ft of torque. In Edmunds testing, the coupe went from zero to 60 mph in 4.3 seconds. Fuel economy is identical to that of the XKR.

Standard safety equipment on the 2012 XK lineup includes traction and stability control, antilock brakes and front side airbags. Side curtain airbags are not offered. The convertible adds pop-up rollover bars. In Edmunds brake testing, the XKR with 19-inch wheels and tires came to a stop from 60 mph in an excellent 111 feet. The XKR-S was about the same.

It's no surprise the 2012 Jaguar XK is an impressive straight-line cruiser. However, the advantages of its lightweight aluminum construction and adjustable suspension become most evident when the roads get twisty as the XK carves precise lines through the corners. The XK might not be as responsive as a Porsche 911, but it's much more nimble than the Mercedes SL.

The current lineup of V8 engines has created an entire new definition of Jaguar performance. Even the base XK is impressively potent, with near-instant response and a wide, muscular power band. The supercharged XKR, meanwhile, is a monster, and it can post acceleration numbers equaling some of the world's best sports cars.

If the XKR is a monster, then we're not sure what that makes the XKR-S -- some sort of British Mothra, perhaps. Even the slightest exuberance with the throttle will set the tires futilely spinning as the traction control system struggles to rein it all in. This is not a car to be taken lightly, yet with equal parts respect and talent from the driver, its increased abilities yield a truly impressive performance machine. The XKR-S's suspension is indeed firmer than the regular XKR's, but compared to other dedicated performance machines like an Audi R8 or Porsche 911, it remains surprisingly comfortable.

The 2012 Jaguar XK's cockpit is well-tailored and inviting. This year's addition of the rotary shift control (it's also in the XJ and XF) is a nice touch. There are some ergonomic glitches, however. The multipurpose touchscreen that operates audio, climate, navigation and phone systems is nice in theory, but in practice we've found it slow to respond and fussy to use. Another downside is getting in and out of the tiny backseats. They can certainly accommodate small children, but most adults will gripe about the accommodations. The cabin can also be a little claustrophobic given its rakish greenhouse and slim windows.

The XK's power soft top takes a scant 18 seconds to lower and is well insulated for a quiet ride when deployed. The XK coupe's trunk can hold about 11 cubic feet of cargo -- much larger than the trunks in the 911 or Mercedes SL-Class and just slightly smaller than the 6 Series or Mercedes E-Class cargo holds. With the top down, the XK convertible can still hold a respectable 8 cubic feet.