What is it?
It's simple really - the XJR is the quickest XJ on sale. And here's another stat for you: it's also the fastest accelerating XJ that Jag has ever built.
And because of that, it doesn't come cheap. Prices start at £92,370, but it's easy to push this towards £100k with a few options.
I'm guessing there's a big dirty V8 under the bonnet?
Correct. It's the same supercharged V8 that sits in the F-Type, but in the XJ it produces even more power. 542bhp and 502lb ft, to be exact. In a car weighing just 1,870kg, that's good enough for 0-60mph in 4.4 seconds, which is competitive with all the major rivals like the upcoming Mercedes S63 AMG.
Or, in other less corporate words, it's bloody quick. Thanks to the supercharger and the relatively low weight of the XJ, the Jag reacts instantly. It feels eager, sharp - not what you'd expect from a large saloon that can seat five in leather-swathed luxury. There are no delays to any of your inputs, whether it's the steering or the throttle or the gearbox. Punchy, refined and with enough edge to make you feel like you've invested in the top Jag.
That all sounds positive. But it's a big car - does it handle well?
Yup. As we said above, because it's a reasonably light car - the S63 weighs 100kg more - the XJ feels nimble. The controls are finger-tip light and there's even a decent amount of feedback through the seat. Unlike other limo-barges, the XJ manages the neat trick of shrinking around you and it certainly doesn't feel unwieldy.
Of course it's no sports car - there are only so many laws of physics that the Jag engineers can overcome - but it also isn't a dead weight like other fast saloons.
What about the ride?
In the main, it's good. Certainly comfortable enough to cope with most roads in Britain, and you don't get shaken up over broken surfaces.
The only caveat we've got, and it's a very minor one, is that it's an ‘R' so the ride is on the firmer side of comfort. You don't waft like in the regular car - no surprise, given that the springs are 30 per cent stiffer than on a normal XJ. And the steering can jiggle a fraction in your hands when it's under hard load.
But then all that is why you bought the R version, isn't it?
So should I buy one?
Definitely. This is Jag at its best - not trying too hard to give the car a ‘yoof' feel with ridiculous spoilers and a loud attitude. The XJ feels happy in its own skin, with the right blend of speed and comfort. One of Jag's finer moments.