Let's start with a simple truth: no matter what people say, you do not necessarily make a car better by making it faster. Ranges of cars, like sprawling cities, tennis rackets and drunken nights out, have sweet spots. Unexpected, near-perfect moments of goodness where the execution completely marries with the premise, where what you hope for unexpectedly becomes what you get. Want an easy example? The 2.7-litre diesel Jaguar XF with the six-speed automatic gearbox is one of these little moments of quiet brilliance, the gem of the XF range; fast, frugal, a bit swish, comfy, relatively affordable.
Which means that the weight of expectation for the XFR must be lounging like a sack of cement on the shoulders of Jaguar engineers right now. Because for £60k, with an all-new 510bhp supercharged V8, this new super saloon needs to create a new high point in the range, be better resolved than the XF D, be the one people point to when you think about the one you'd buy, money no object. Otherwise, what's the point?
So first we have to assimilate what we expect from this fast Jaguar. First, it needs to look like a Jag with added gumption rather than some tarted-up pretty boy covered in the acne of flashy add-ons. And it does. The XF is a pretty shape in the right colour, and the XFR does nothing too insensitive or peverse. Indeed the modification count makes for a relatively short list upon casual observation. There's a bigger grille on the front, bigger nostrils, slightly lower stance (it's been dropped 27mm), quad exhausts, a small, almost vestigial boot spoiler, a couple of sculpted side skirts, a light spattering of ‘R' emblems - you might even pass it by if it wasn't for the reasonably sized 20-inch alloys with ‘supercharged' etched around their centres. Subtle rather than particularly showy then, but with a bit of added brawn. Inside it's more of the same - the usual beautiful XF interior with some subtle ‘R' badges and more bolstered seats -if it ain't broke and all that.
Second, we need to assess the performance potential; no good shouting about your forced induction if there's no speedy ambush to match the signwriting. And that's pretty much a given when you look at the bare stats; 510bhp, 0-62mph in 4.9 seconds, a limited 155mph top end and in-gear acceleration times to make your eyes water. If you look at the more real-world acceleration between 50 and 70mph, the XFR takes 1.9 seconds. That's quicker than pretty much anything and delivers it all and with the lowest C02 figure in the class. OK, so 292g/km isn't spectacular in absolute terms, but for 500-odd bhp? That's good. In theory then, a British rival to the world of bruising super-saloonery, a kick up the arse for the M5, the RS6, the E63?
On paper, yes. In reality? No. Not really.
You see, the XFR isn't trying to be an M5, an RS6 or an E63 beater, it's trying to be a very fast Jaguar. So it doesn't jiggle or dance around at slow speeds, doesn't telegraph the fact that it's the ‘performance' version in everything it does. Drive it around slowly and you really don't get much speed-related shoutiness at all - just the feeling that this XF has nicely connected steering and deals with bumps in the same calm manner as any other Jag. It is, when all's said and done, a bit normal. Very easy to get on with. Quiet. Calm.
Oops. Sounds like Jaguar has screwed up here doesn't it? It's made a performance car without any performance feel. Well, again, no. When you get around to unfurling that new engine, the XFR will peg your ears back in a most emphatic fashion. Make you do some breathy swearing, mainly because, from all the nudges and winks and responses that you've collected up to now, the XFR doesn't feel like it will launch quite so hard. And it's so easy to access. This motor has huge bottom-end shove, partly due to the whacking great supercharger that delivers 461lb ft of torquefrom 2,500rpm right the way until it drops off at 5,500rpm. That means that roll-on acceleration and standing start growliness are second to none; stamp on the XFR and it will respond hard, without lag and without dropping a gear like you have to in some of the opposition.
Direct-injection allied to the blower means that the new 5.0-litre delivers in a massive tidal swathe of grunt, never realising a peak nor dropping into a cammy hole. There are no soft-spots, no sudden raging VVT explosions. It just keeps on pushing at the horizon, barely taking a breath between gears. The new adaptive gearbox software deals with full throttle upchanges without a significant lurch, blipping the throttle and tightening itself up as you change the modes for the 'box and suspension. It's quick indeed. But never does it feel fussy, clumsy or compromised.
In fact, it feels quite a lot slower than it actually is. That's partly down to the fact that, from the inside, the XFR really isn't loud enough, and partly due to the fact that, in being so fussless, the car disguises its sheer speed in a little bubble of competency. It's only when you hit the horribly final-feeling limiter that you realise just how fast you shouldn't really have been going - 155mph came around very smartly indeed. Incidentally, a derestricted XFR will potentially hit around 195mph. That's frighteningly quick.
To cope with all the new world power, the XFR gets Adaptive Dynamics, which replaces the old CATS active suspension. This time it's more variable in its responses - it can monitor and alter the dampers some 500 times per second and allow the car to float over bumps rather than plough into them. Allied to that is the new Active Differential Control (ADC) which can ‘torque-vector' the available push to the wheel with most grip. It can also play with the diff to get lairy (the ‘Handling Functionality' mode is just a tight diff and DSC off hooligan's charter), or do clever stuff like partially lock the diff if you brake suddenly, and change lanes for added stability. When you're just tooling around town it acts essentially as an open diff, instantly negating all the NVH and general spitefulness of a tight mechanical locking LSD, which wouldn't suit the car's character.
To be honest, if you leave the various buttons alone, the XFR can feel a little numb. You can immediately feel the trade-off between turn-in precision and the benign cruiseability that's such a boon in ‘normal' driving (ie 80 per cent of the time). There's a fair bit of body roll, and even though the car settles quickly, high-speed roll-ins need some concentration. It starts off feeling a little ambivalent, but once you spend some time getting used to the range of talents, it starts making a whole heap of sense.
In and through a corner, the new suspension and diff work supremely well. If you do a bit of button-pushing, set the car for ‘Trac DSC' and stick it in ‘Sport', you'll get a car that isn't miles away from the standard settings - it doesn't suddenly go rock hard and start smashing your teeth out - but one that allows you to make more use of the grip available. Be faithful in your responses to it and it generates a lovely loping and intensely speedy rhythm. Turn-in is nicely controlled and the car settles quickly, feeling like it just releases into a touch of power-oversteer right at the end of the corner - graceful rather than racecar, but no less satisfying for that.
The thing is, the fast saloons that we're used to have a nasty habit of addressing 180mph dynamics with precious little realisation that the car will spend 90 per cent of its time doing significantly less than 80mph. Drive an M5, and there's always the faint whiff of accusation that you're not driving the bloody thing hard enough. A seven-speed V10 that revs to 8,500rpm and only delivers a torque peak north of 7,000rpm will do that for you. If anything, the Jag is more in-keeping with a big-hitter AMG - except with about a 50 per cent better ride/handling balance. When you think about it, most of the über-quick more-doors have a wonderfully paradoxical nature, in that they purport to carry four people and luggage, and yet then have the slow-speed and rear-seat manners that ensure no bugger ever wants to ride in the back.
The XFR isn't trying to be that kind of car. It isn't defining itself against the marketplace - which is totally refreshing. An M5 is faster, in my opinion, more precise, more connected. But, compared to the XFR, it's a hyper-agitated one-trick pony. The RS6 could leave the XFR for dead. In it you'd be so bored doing it that precisely nobody would care. In the same way that they managed with the XF D, Jaguar has definitely not tried to blindly ape the dynamics of the German opposition, but ploughed its own little engineering furrow, and the car is the better for that.
The truth is that if you chase BMW or Audi, all you'll ever be is a perverse facsimile with a feline twist. Jaguar realised that when it began development of the new XK and subsequently the XF - it is simply not enough to offer a wonky interpretation of something else. The XFR once again demonstrates how confident Jaguar is feeling in knowing what a Jaguar should be, and how it should feel. That makes for very appealing cars - they have a strong sense of character, of self. In essence, a modern Jaguar is the kind of car that you might choose if you have precisely nothing to prove. The XFR just makes sure that if you have to, your argument will be a strong one.