BY Rob Beintema

"Just a sec," the track marshal said as he held me in place, his arm stretched across my windshield.

The morning was fresh and clear with that delectable hint of hot brakes and burnt rubber in the air.

A few cars were finishing their laps, their tire squeals echoing across the improvised track that had been laid out across the tarmac of the Niagara District Airport.

I never mind the waiting. It just sharpens the edge of anticipation. And I'd been anticipating this for a while.

The 2010 Jaguar XFR.

I'd spent some time in the XFR a few weeks before. But there are certain test cars you don't get enough of during the year, cars capable of so much more than you could possibly explore on city streets, or even on quiet country back roads and empty highways.

You can only touch on their potential, but you check your regrets and add another line to that mental list of cars worth a second look at the track sessions of AJAC's Car of the Year competition.

As I waited there at the track entrance, I racked the seat forward another inch, re-checked the Dynamic Mode setting and adjusted the mirrors in the unlikely event that someone would actually catch up to me.

"Okay," he said, and the arm dropped. "Go!"

Hit the gas and all hell breaks loose, the tire squeal of 20-inch wheels clawing the asphalt quickly overwhelmed by thunder, the engine roar bellowing from under the hood and out of the exhaust as 510 hp of supercharged mayhem erupts forth and the world gets fast very, very quickly.

I'm sucked back into the seat, my adrenaline surging to keep pace with the acceleration.

"Holy Moly'" I mutter because we're already up to the first chicane, the G-forces rotating to lateral loads as we carve a path from one side of the runway to the other. And back again. I'm gritting my teeth. Back and forth and back and forth.

It's poor etiquette to knock the pylons flying on an autocross course. On the other hand, if you don't clip one once in a while, well, you're not really trying.

But, so far, the XFR was minding its manners, thanks to a taut four wheel independent suspension supported by a blend of traction control technologies, an Active Differential Control and an Adapative Dynamics system that adjusts the damper rate instantly to driving input.

Every time the car squirts out of a corner, I'm impressed by the sheer muscle of acceleration. The XFR goes from 0-100 km in 4.9 seconds. Its power ratings of 510 hp and 461 lb-ft of torque place it in a very exclusive club of high performance supercars. At that particular 2010 Car of the Year TestFest, out of the more than 50 vehicles tested, only the Audi V10 R8 and Porsche Panamera were in the same ballpark, powerwise at least.

The XFR was substantially heavier than both competitors in its Sport/Performance over $50K category - the Audi S4 and Mercedes-Benz E-Class Coupe. But despite carrying 200 kg more mass than the S4, the sheer power of the direct injection supercharged 5.0-litre AJ-V8 gave it the best power-to-weight ratio in its class. It is the ball peen hammer to the S4's scalpel, bludgeoning track times with pure muscle.

The three or four laps pass in a blur and I'm suddenly back on a country road, passing sedately along rural roads and down long vineyard lanes.

This is the second side of the XFR's personality, the part where James Bond slugs his way out of a bar room brawl and strolls into the cocktail lounge adjusting his tux.

Despite its brawn, there's no lack of elegance to this car. The sleek lines of this mid-size luxury sports sedan carries both the future and past flavours of the brand, with heritage cues from the Mark VII and Mark 2 sport salons of the 1950's, bolstered by hints of the XK. But the low-slung shape of the past is gone, the wedge-like profile rising to high haunches with a new Jaguar design language. This is the slipperiest Jaguar ever built with a 0.29 co-efficient of drag.

Any doubts about its identity, after the mesh grille, "supercharged" embossed hood louvres, gill slits and XFR badging are put to rest by the Jaguar name and "leaper" on the back of the boot (which still sounds better to me than "trunk lid").

Inside, the XFR shows clean and elegant lines sweeping across the cabin and aluminum dashboard. Stab the start button and the car awakens with four vents powering up and open, the unique rotary Drive selector knob rising from the console, its operation supported by sequential shift steering mounted paddles.

The well-bolstered heated and ventilated sport seating is firm yet pliant and the quality and construction levels are impeccable. The interior is beautifully underscored at night with Phosphor Blue halo illumination and ambient mood lighting.

Drivers who care more for perks than performance will find the XFR all-day comfortable with none of the pent-up nervous energy of some high-powered performers. With a standard equipment list that includes heated steering wheel, front & rear parking aid with rear camera, Blind Spot Monitor, DVD-mapping with voice guidance, a 440-watt Bowers and Wilkins Surround Sound system and other items too numerous to mention, it comes fully-loaded as expected at this top end of the lineup.

There's just so much to explore in a car packed with this much

So you can imagine the pressure on a judge in this category, the need to insure that every aspect of the car has been investigated thoroughly and accurately.

Which, I guess explains why I was back again, the arm stretched across my windshield, the track marshal turning to look back at me with raised eyebrows and a knowing grin.

"Weren't you out in this earlier?" he asked.

"Yeah," I answer. "Um, just, uh, checking a few more things . . "

The arm dropped.

"Go!"