ROANOKE, Tex. — At Texas Motor Speedway near Fort Worth, we’re running lickety-split over the serpentine in-field circuit in a performance-tuned 2012 Jaguar XKR sports coupe with a huge herd of horses hitched beneath the exaggerated hood.

Strapped in the bolstered shotgun seat, Roberto Guerrero — the Formula-One/CART/IndyCar champ — offers instructions on how to carve the fastest line around each tricky chicane in the wiggly 1.5-mile loop course.

Guerrero is one of six professional driving instructors in the Jaguar Performance Driving Academy, which unfolds four times a year at various race tracks around the country. The one-day driving school — teaching acceleration/launch control, emergency lane-change maneuvers, braking and cornering drills as well as handling exercises on autocross and slalom courses plus full-track laps — is complimentary to buyers of new Jaguar XKR and XFR performance models, or $1,850 for non-owners.

Spending a day in the driver’s seat of a high-powered 2012 Jaguar XKR on a race track shows off the vehicle’s incredible sporty manners and triple-digit speed thrills.

But the 2012 Jaguar XKR is so sensuous and handsome we like to park it and simply treat our eyes to all of those slinky bulges and curves and automotive body shapes.

Long in the prow and low in stance, the GT-style coupe presents a tightly sculpted structure with muscular fender bulges rippling around enormous low-profile tires and a low arching line of the roof drawn across the snug and sporty 2+2 cockpit.

For 2012, the exterior shell of base XK Portfolio and sport-geared XKR models has been revised with revamped fascias front and rear, restyled narrow headlamps and LED running lights. XKR dresses in performance paraphernalia including a grille with black mesh insert and special painted alloy wheels branded with R emblems.

Also for 2012, Jaguar’s slick GT series gains a new top-dog model, the XKR-S packing a supercharged V8 blowing out to 550-hp.

XK cars resurrect styling cues from Jaguar’s 1960s icon XK-E, thanks to the extended hoodline and aerodynamic prow.

Yet the chassis of 2012 XK models is strictly state of the art as an unconventional unibody structure composed of lightweight aluminum rather than weighty steel.

Choosing aluminum as the car’s building blocks forges a stiffer structure because it comes together with self-piercing aluminum rivets and heat-cured glues in techniques lifted from the aerospace industry to create an ultra-rigid frame measuring much stiffer than a similar body crafted with steel.

XK’s wheelbase stretches nine feet long and the wheel track width draws more than five feet wide to fashion a platform of substantial size with room for the 2+2 cockpit.

As a premium personal luxury car geared for high performance, the XK design scheme tucks between the long prow and curt tail a passenger compartment with only two doors and seats for up to four riders. Space in the cabin is admittedly modest in the rear but up front on broad buckets clad in twin-stitched leather hides there’s virtually every conceivable amenity aboard for luxurious comfort.

Slabs of polished hardwood line dash and console, and the instrument panel houses round analog gauges in easy-to-read electronic displays.

The center dash shows a touch-screen panel to manage climate, entertainment and navigation systems.

Standard XK Portfolio equipment includes a DVD navigation system, keyless push-button start device, xenon high intensity discharge (HID) headlamps, auto-dimming mirrors, rear parking assist (RPA), premium surround-sound Bowers & Wilkins audio system with in-dash six-CD changer, satellite radio and USB interface, and 19-inch alloy wheels.

2012 Jaguar XKR standards go further with unique 19-inch alloys, piano black wood veneer dressing switch gear, a heated windshield, active headlights and adaptive cruise control, plus upgraded brakes and exhaust.

Then the optional new Dynamic Pack brings 20-inch wheels with suspension revisions, a larger rear wing, lower front aero splitter, rocker sill extensions, rear aero diffuser plus big brake calipers painted in vivid red.

All XK models employ a four-wheel independent suspension in aluminum, with double wishbones in front and a multi-link arrangement in the rear plus Adaptive Dynamics active damping.

Speed-sensitive variable-assist power rack and pinion steering and four-wheel disc brakes with computerized anti-lock brake system (ABS) controls plus electronic brake distribution (EBD), emergency brake assist (EBA) and corner brake control (CBC) improve motion maneuvers for XK cars. Further, a dynamic stability controller (DSC) is aboard, and XKR adds active differential control (ADC).

Jaguar’s big V8 — displacing 5.0 liters off an aluminum block with four-cam configuration — motivates XK cars. For XK Portfolio the naturally aspirated V8 delivers 385 hp at 6500 rpm and 380 lb-ft of torque at 3500 rpm.

2012 Jaguar XKR acquires an Eaton blower with dual inter-coolers to fashion a supercharged plant. It runs to 510 hp at 6000-6500 rpm with torque of 461 lb-ft between 2500 and 5500 rpm.

And new XKR-S scores revised fuel mapping and an active exhaust for boosted power to 550 hp at 6000 rpm and 502 lb-ft of torque at 2500 rpm. As Jaguar’s most powerful road car ever, the XKR-S races from zero-to-60 mph in 4.2 seconds with a top speed (electronically limited) of 186 mph.

Jaguar sets the MSRP for a 2012 XK Portfolio coupe at $84,500. The 2012 Jaguar XKR coupe tallies to $97,500, while new XKR-S caps the series at $132,000.

2012 JAGUAR XKR MIDSIZE LUXURY COUPE SPECIFICATIONS

• Description: Mid-size luxury 2+2 GT coupe
• Model options:
  • XK Portfolio
  • XKR
  • XKR-S
• Wheelbase: 108.3 inches
• Overall length: 188.7 inches
• Engine size:
  •  XK: DOHC 5.0-L V8
  •  XKR: DOHC 5.0-L V8/SC
  • XKR-S: DOHC 5.0-L V8/SC
• Transmissions/speeds:    
  • XK: Auto/6/MSM
  • XKR: Auto/6/MSM/LSD
  • XKR-S: Auto/6/MSM/LSD
• Rear/front drive: Rear
• Steering: Power rack and pinion
• Braking: Power 4-disc, ABS/EBA/EBA/CBC/DSC/ETC/ADC
• Air bags: 2 (front), 2 (side)
• EPA mileage est. city/hwy.:
  • 16/24 mpg: XK Portfolio
  • 15/22 mpg: XKR
• MSRP, est.:
  • $84,500:   XK Portfolio
  • $97,500:  XKR
  • $132,000: XKR-S