Overall rating: 4/5
Hardcore handling and race-car punch haven't ruined the Jaguar XF's comfort or refinement and the XFR-S is as at home on the track as it is on the road. It's more expensive and more thirsty than a BMW M5, though, even if it does feel more special.
In the metal 4/5
Don't worry; you don't have to have it in a shade of blue that threatens the health of your optic nerve. French Racing Blue might be the distinctive launch colour for Jaguar's hardest and most focused sports saloon ever, but the XFR-S can be had in more subtle, more Jaguar-y shades of Dulux. The massive rear spoiler, which looks rather as if a First World War biplane has made an emergency landing on the boot lid, is also an option and can be replaced by a more discreet lip spoiler. Both are fully functional though, and contribute, along with a rear diffuser, to cutting rear-end lift by as much as 69 per cent at speed.
Even without the big rear wing though, the XFR-S is clearly a more aggressive looking car than the 'cooking' XFR. The engine's extra 40hp is signalled by a deeper front bumper with bigger air intakes and vertical turning vanes to direct the airflow to where it's supposed to go. Dark grey 20-inch 'Varuna' alloy wheels are tightly wrapped around massive 380mm front brakes (still steel - Jag's not ready to offer the XKR-S GT's carbon ceramic brakes as an option yet) and the whole car appears tightly hunched and ready to propel itself forward.
Inside you'll find the familiar XF cabin, which is no bad thing, and here it's enlivened by leather with a simulated carbon-fibre weave (sounds odd, looks the business) and contrast stitching in the same retina-burning blue as the exterior. This may be a performance-focused, hardcore super saloon, but it's not stripped out by any means, as the touch-screen satnav (which still lags behind its German rivals' in usability terms) and stonking Meridian sound system attest. As with all Jags, this is a nice cabin simply in which to be.
Driving it 5/5
Wow, it's quick. Perhaps that's rather an obvious thing to say about a medium-sized saloon packing a 550hp punch, but the XFR-S feels wonderfully aggressive and punchy as you nail the throttle from a gently rolling start. Jaguar's claim of 0-100km/h in 4.6 seconds feels entirely believable and, if anything, a touch conservative.
The steering is weightier and more resistant than that of the standard XFR or XF. There's no change to the rack itself, just tweaks to the software and the pressure valves, but the result is a car that changes direction with a mere sniff of input and which feels instantly more alert and up on its toes than the bigger XJR - which uses the same engine and gearbox.
There's a terrific snarl from that engine when you accelerate hard; not the soft burble of an American V8, but a much more complex, layered sound. Jaguar has turned down the whistle from the Roots-type twin-vortex supercharger, so the car goes and sounds as if it has no forced induction at all, and there's none of the (admittedly small) turbo lag that you get with the current 560hp BMW M5. The eight-speed automatic transmission is fitted with a QuickShift mechanism that makes it feel more like a race-focused twin-clutch gearbox than a conventional torque converter automatic when you're using the wheel-mounted paddles to take manual control. It elicits the most delicious bark from the engine as the software blips the throttle on downshifts too, as if someone is poking a narky wolf with a pointed stick.
Push the XFR-S really, really hard (on the track of course) and it will eventually understeer as the front tyres begin to give up the ghost and overheat, but until then it is remarkably capable, and it's ability to haul down to a chosen apex from high speeds is astonishing in what is, remember, a quite heavy, luxurious four-door saloon. Certainly you're never going to get anywhere near its limits on the public road, unless you have some sort of fetish for wearing prison clothing, and if you're in a mood to play, then big, hilarious power slides are there for the taking.
It's also astonishingly comfortable. Our first introduction to the XFR-S was on the track, and following its demonstration of flat, level and precise cornering, we were expecting it to be impossibly harsh and bumpy on the open road. But it just isn't. It's smooth and almost soothing. Firm, certainly, and a little unsettled if the surface gets really rough, but considering the handling, performance and general air of being well 'ard, the XFR-S rides with amazing levels of comfort. And yes, that's even still true when you toggle the button for the dynamic suspension mode.
Is it as good as an M5? Yes, I'd say so and in fact feels more progressive and predictable than the fast BMW. The M5 switches in an instant from well-specified 520d to howling mad monster of torque - the XFR-S, despite looking much more aggressive, actually feels a little more pliable and easy on the nerves than the BMW. It's also simpler. Even though BMW removed a layer of complication when it switched from the too-many-modes-for-common-sense E60 M5 to the current F10 model, the fast Beemer still feels closer to an all-digital jet fighter. You're instructing a computer to carry out your wishes, it's fully fly-by-wire. By contrast, the Jag feels a little more analogue, a little more old school. You feel in control of an utterly capable and composed vehicle. It's a subtle difference, but a telling one.
What you get for your money 3/5
This is where the XFR-S falls down a bit. A sticker price of around €160,000 is significantly more expensive than what you pay for an M5 or E 63 AMG saloon and both the Germans are more powerful and more technologically (especially electronically) advanced. The Jag hits back with better equipment as standard, and also a sense that it's a bit more bespoke, a little more individually crafted than either of its main rivals. It helps that, compared to the number of XFR-S that will be built, both the BMW and the Mercedes will be effectively as common as muck.
Worth Noting
Astonishingly, this may not be the hardest-core version of the XF that we will see before the model gets replaced in 2016. Andy Dobson, programme manager for both the XF and XJ model ranges, refused to be drawn when we asked him if this is the ultimate iteration of the current XF's hardware, but simply said "for now, this is it." Jaguar has an even more powerful version of the V8 engine (in the track-based XKR-S GT) and also such items as carbon-ceramic brakes in development, so it's possible that we may yet see a final 590hp, ceramic-braked ultimate XFR-S GT before the end of the current car's life.
Summary
You pay handsomely for the Jaguar XFR-S. It's both more expensive than its main rivals and its styling is love-it-or-hate-it in your face - much more aggressive than the softly-softly Jags of old. It's not too hard-edged to be considered for daily driving duties but potentially the slower, less powerful standard XFR (which is, let's face it, hardly sluggish) is the better bet for all-round use. What the XFR-S does really well, though, is remind the world that Jaguar was the original sports saloon maker. Way before M or AMG badges ever adorned a road car, Jag was making sexy, fast four-doors beloved of racers and bank robbers alike. The XFR-S puts Jag, at a price, right back in the heart of that arena, able to trade blows with the BMW and Merc and come up smiling.