They're mechanically identical to the standard cars, but there's something rather special about the XJR 100 saloon, XKR 100 coupé and XKR 100 convertible limited editions launched to mark Jaguar founder Sir William Lyons's 100th anniversary.
All three models come with anthracite paintwork, charcoal leather upholstery, DVD satellite navigation, an R Performance steering wheel, uprated sound system, reverse park warning, rain-sensor wipers and a number of other extra features.
Well, wiper singular on the XJR, because even the 100 version has that deeply unimpressive single wiper which I do wish Jaguar would get rid of for something better. No high-performance car - and this surely is one! - should have both top corners of the screen unwiped.
The XKR is more highly modified. Coupé and convertible have Recaro front seats and various items of aluminium trim, including the pedals. Only the coupé gets an R Performance handling pack as standard XKR 100 equipment, although the Computer Active Technology Suspension is fitted to the whole series.
Some of the newly featured up-grades may make their way, next year, into the R Performance catalogue, although exactly which ones will be chosen hasn't been officially announced yet.
Items which have been recently made available in the R Performance range include the latest, and highly impressive, nine-spoke BBS Montreal silver-finished alloy wheels, 19" on the XJR and 20" on the XKR, and cross-drilled Brembo brakes.
Jaguar is building just 500 of the XJR 100 saloons and the same number of XKR 100 models, split according to demand between coupé and convertible, and they're going fast. That's as in selling well, and not just a reference to their performance.
But you can't avoid referring to their performance, because these are tremendously quick cars. They all use the supercharged four-litre AJ-V8 engine. And they're all fitted with automatic transmission operated via the familiar Jaguar J-gate selector, which is something else I just don't see as being good enough for cars in this class.
However, whines and whinges like that don't detract much from the pleasure of driving cars which not only look terrific (the XJR 100 most of all, against its rivals in the high-performance saloon class) but are also tremendously quick.
The saloon has red stitching to all its leather trim. In some hands, this would be garish, but Jaguar is very subtle in its approach, and the stitching undoubtedly enhances the interior without being in any way obtrusive. Grey-stained bird's-eye maple woodwork is standard, and Jaguar proved a long time ago that that unusual colouring is smart and yet discreet.
From a space point of view, this saloon is like a whole line of Jaguar predecessors. It's roomy up front, but seriously restricted in rear seat accommodation. You have only to compare the overall length with the wheelbase to appreciate why, and there's nothing that can be done about it. The boot is much better than in the original XJ saloons, though.
However, let's leave the interior and consider the XJR 100 on the road. There's very little to be said, actually, apart from a string of superlatives. On some hilly routes in the CARkeys neck of the woods, the test car was simply magnificent. It's not just a matter of awesome power, although that's certainly there, but also of how well Jaguar's chassis engineers have managed to put that power securely onto the tarmac, on the straights, on the corners and on the gradients. Tremendous braking capability, too.
It's remarkable to look at the performance figures and note that even the enhanced specification of the XJR 100 - in black, a really mean-looking Jack Palance of a car, if you follow me - still doesn't take the price to £60,000.
The XKR 100 coupé (we didn't get our mitts on a convertible) seems more of a fast, long-distance cruiser, the kind of car for which the expression Grand Touring was coined. It's simply stunning in appearance, without any of the styling quirks and quiddities you see in some minimal-production Continental supercars which may be lauded for their ultra-high perfomance, but couldn't possibly be used for transport every day. They're likely to be temperamental, and some of them give a frighteningly inefficient view of surrounding traffic on urban roads.
But while the Jaguar may be OK for everyday use, it's only in a dictionary that that definition would merge with mundane. Floor the throttle and it simply warp-factors away. There are always oohs and aahs when some higher-priced supercar offers 0-60mph acceleration in something close to five seconds. The XKR coupé has been in that vicinity for several years now, and yet even the special edition price doesn't breach the £70,000 limit.
Standard equipment includes the adaptive cruise control which Jaguar was the first mainstream manufacturer to offer. There we are again - high-speed autoroute, autobahn or autostrada motoring, with the XKR in its element. Two-up, of course. The rear seats are virtual.
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