"Track capable". That's how Jaguar's ride and handling legend Mike Cross describes the new XKR 75, the massaged XK that's been specially created to celebrate the marque's 75th anniversary.
Track capable is certainly what this XKR feels like as Cross fairly flings it across the Warwickshire countryside. But although XKR 75 owners will - probably - make the odd trip to the Nürburgring or Silverstone the Fastest XKR, like every other Jaguar, has to be a road car first and foremost.
"Jaguars have to be relaxing and cosseting as well as fun," says Mike. "Take the XFR I'm running at the moment. Most of the time I use it for the daily grind of commuting to and from work, and when you're stuck in traffic or you're tired it's nice to have something comfortable and undemanding. But when you want to go for it you can. This XKR is like that, but with an extra focus on the performance."
This is achieved by tweaking power by 20bhp up to 523bhp, while torque jumps from 461lb ft to 483lb ft. Jaguar has also raised the speed limiter to 174mph, and cut the 0-60mph sprint from 4.6secs to 4.4secs. But the headline figure is 0-100mph in a stunning 8.9secs.
The front springs are 28 per cent stiffer, the rear springs 32 per cent stiffer and there's a revised rear suspension upright for increased camber stiffness. The adaptive damper control software has also been tweaked and ride height reduced by 15mm at the front and 10mm at the rear. To help stability at the new-found higher top speeds, the Active Differential Control now reduces steering sensitivity at very high speeds.
Pitch it into a corner and, provided you haven't arrived with far too much speed (which is quite likely given the utterly given the utterly relentless acceleration), and the XKR 75 will turn in with a surprising alacrity.
Once you're into a corner there's more grip, too, thanks to the bigger tyres - and that's something you can feel even from the passenger seat. Another thing I notice from the passenger seat is just how much traction there is, as Cross pretty much gives it the beans out of almost every corner (commendably, one of the first things he did when he got in the car was to switch ESP fully off).
The XKR's pace and poise over bumpy, ridged country roads is little short of astounding: this is getting genuinely close to supercar territory. Although the way the XKR absorbs bumps, bounces, and road ripples is, as we've come to expect from Jaguar these days, more akin to the behaviour of a big Lotus than it is to that of a more traditional supercar, despite the frankly massive, steamroller section 20-inch tyres.
Not wanting to relieve Jaguar of an £85,500 car (that's £10k more than the regular XKR), nor of its vehicle development chief, by crashing I take it easy at first. Besides, for some reason the previously traffic-free roads are suddenly filled with an endless string of bin lorries, OAPs and general dawdlers. Just as Mike said it would be, however, the XKR 75 is more than happy to bimble along, with only a slightly more nuggety ride than you might get in a standard XKR to remind you of the car's extra performance edge.
You may have also inadvertently been distracted by the booming gargle of a new active exhaust, which makes the XKR 75 sound mightily fruity. You'll also be treated to an occasional over-run crackle, as the ZF six-speed auto blips the engine for you as you move down the gears via the wheel-mounted paddle shift.
That kind of sums up the XKR 75. The differences between it and the regular car are small - low single digits if you want to put it into percentage terms - but they add up to make a reasonably significant difference. This car isn't what the Aston DBS is to the regular DB9 - it's too sophisticated and subtle for that. But it is heading in that direction.
For the moment the XKR 75 is a strictly limited edition model (there will only be 75 of 'em and there are no official plans for a mainstream XKR with the 75's tweaks.