The first thing to get your head around is that Jaguar has built an F-Type capable enough of taking a serious bite out of the Porsche 911 Turbo. We loved the V8-engined convertible, but it was the love one might feel for an unruly and slightly potty Labrador – putting it in the slips against anything overly serious felt too often like folly.

The R-badged coupe is a rather different prospect. For a start, where previously there was only insulated fabric or plain old fresh air, there’s an exquisitely beautiful set of aluminum beams strung beneath the A and B pillar. By sealing the roadster’s part-finished monocoque shut, Jaguar has delivered the most torsionally rigid car it says it has ever made.

Better stiffness – the suspension rates on the all-round double wishbones have followed suit – has provided the engineers with an excuse to liberate even more of the supercharged 5.0-litre V8’s potential. Its 542bhp output – 54bhp more than the rag-top - has previously been preserved for weightier prospects like the XKR-S and XFR-S.

Its introduction in the 1650kg F-Type means the R comes only 10bhp shy of the 552bhp rendered by the twin-turbocharged 3.8-litre flat-six in the latest Turbo S.

Peak torque is on a similarly level playing field: 502lb ft vs 516lb ft (although the 911 will deliver 552lb ft on overboost). But where the Porsche is slyly capably of shifting its power between two axles, the Jaguar sends it exclusively to the rear end, trusting the second generation of its Electronic Active Differential and a newly introduced torque vectoring system to make sense of it.

The tone of delivery is equally divergent. We’re used to Jaguar teasing some extraordinary notes from the outboard-mounted quad pipes, but this time it has gone to Liberace levels of excess. In Dynamic mode, the bypass valves default to straight-through drama at all speeds, meaning that every inch travelled is accompanied by an ear-splitting eight-pot mewl or off-throttle pop.

Steve Sutcliffe drives a Jaguar F-type R coupé prototype.

It is of such melodramatic, look-at-me quality that you’d most likely shy away from its virtues in the company of others – and then leave it permanently turned on when alone. Too much of a good thing can, after all, be wonderful. Or not, in the case of the 911, which transports you from a standing start to beyond the horizon with all the expediency and drama of a flash drive.

Refined progress comes naturally to the Porsche; its remarkable high-speed stability means you could absent-mindedly study the concrete pylons on the Second Severn Crossing at 150mph. But you do not indulge in its mighty performance in the same way as you do in the Jaguar. The F-Type’s throttle wants to put a smile on your face; the 911’s just wants to place you three or four miles down the road. 

Admittedly it does this flawlessly. There is more of a whip-crack to the dual-shift PDK’s downshifts than is found in the Jaguar’s ZF-supplied eight-speed automatic, and despite featuring exhaust gas-dependent turbochargers, it spools up more immediately too. For the most part it also rides immaculately, simmering intimately on the softest setting of its adaptive dampers.

Read our full road test of the Porsche 911 Turbo here.

Only by striking a nasty seam or a swollen cat’s eye does the suspension’s tight-rope act become noticeable; the apparently small-scale collision rippling through the Turbo’s tightly-wound chassis and into the driver’s seat. It’s this kind of intrusion which the F-Type – even in wound-up R format – does so well to avoid. Jaguar’s restless Adaptive Dynamics system defaults into the kind of accommodating lope that simply doesn’t include the concussive twang ordinarily indicative of a serious sports car.

There is more body movement as a result (notably, the R actually rides better in ‘Dynamic’ mode than it does in its standard setting) but, correspondingly, there is a broader opportunity to relax into its stride. Where you tend to drive the Porsche with the set jaw and locked arms its determination warrants, the Jaguar elopes with your easygoing side; making every mile markedly less of an effort.

In many ways, the dynamic switches places on a more challenging road. The 911’s iron-willed attitude to forward progress means its lateral grip is as forceful as its straight-line thrust. Its colossal footprint and the weightiness of its steering encourage increasingly huge inputs, meaning you begin to lean on its immense traction almost senselessly.

By mid-corner, with the torque already dramatically vectored, the Turbo will be sending as much power forward as it does rear – meaning any half sane, road-bound effort to get better acquainted with its limits tends to result in understeer. Even with a damp, empty moor laid on, adjustability and playfulness are secondary concerns.

Watch our video review of the Porsche 911 Turbo S.

No one could accuse the F-Type of such bloodlessness. Where moistures persists, the Jaguar retains a less tenacious hold on the road without a driven front axle to share the torque burden, and such traction shortfall is occasionally obvious. But, in contrast to the open-top, there’s a kernel of firm confidence in everything that the new coupé does.

 Its unremitting power delivery no longer seems daunting. Flooring the convertible could feel like a dicey exercise, but in the R coupé, for all its wheel-spinning potential, the even higher output seems tailor-made and keenly deployable. The lightly fettled steering is more responsive than the roadster’s, too, and sitting, as you do, just forward of the F-type’s rear axle, such accuracy is essential to allow you to position the long nose that bit more sweetly. 

From there, in almost any corner imaginable, the chassis takes over. Best experienced on the road with some of the electronic shackles loosened (the TracDSC readily obliges), the R flaunts its sublime front-engined, rear-drive balance at every opportunity, clamping you to an apex only for as long as you want before a slither of extra throttle changes the back end’s attitude. 

If that sounds like the playfulness you’d find in any grunty rear-drive car, think again. The subtlety and obedience of the breakaway isn’t far short of astounding. And as the R is so good at telegraphing its whereabouts, you’re free to dip in and out of the excess as much as you like.

Click here to read a review of the entry-level Jaguar F-type coupé.

That choice is at the heart of what makes the car so special. Unlike the all-wheel-drive 911, you never stop wanting to interact with it. The Turbo wants to be the ultimate salve to the modern headache of A to B; as easy to drive as a hot hatch, supercar fast in all weathers and as cleverly refined as a luxury saloon. The 991, particularly in its vastly expensive Turbo S guise, covers these bases expertly – and is no less giddying when driven fast. 

But the F-Type’s effervescence serves to underline what’s missing from the Porsche’s repertoire. Its huge, atmospheric pace and rousing handling at one end would be less remarkable were they not mingled so keenly with a sense of genuine companionability at the other.

It is that breadth of ability and the insistence that you enjoy yourself at every turn which makes the F-type R coupé not only more compelling than the 911 Turbo, but one of the best cars on sale, period.

Jaguar F-type R coupé

Price £85,000 0-62mph 4.2sec Top speed 186mph Economy 25.5mpg CO2 259g/km Kerb weight 1650kg Engine V8, 5000cc, supercharged, petrol Power 542bhp at 6500rpm Torque 502lb ft at 3500rpm Gearbox 8-spd automatic

Porsche 911 Turbo S

Price £140,000 0-62mph 3.1sec Top speed 197mph Economy 29.0mpg CO2 227g/km Kerb weight 1605kg Engine 6 cyls horizontally opposed, 3800cc, twin-turbo, petrol Power 552bhp at 6500-6750rpm Torque 516lb ft at 2100-4250rpm Gearbox 7-spd dual clutch automatic