It can't be easy being Lamborghini. It has embarked on this plan to design and engineer cars that are now routinely the fastest production cars around you-know-where in Germany, while knowing that 95 per cent of its cars' owners will never go near the place, nor any other circuit, other than for perhaps one quick scare.

So on the one hand, it has to just punt out the fastest cars in the world. And on the other, said cars have to be generally exciting but also approachable and safe enough for people whose closest association with a 6min 44sec Nurburgring lap time will be the cover of a book on their coffee table.

Which brings us to the Lamborghini Aventador SVJ, current keeper of the production car Nurburgring lap record, at 6min 44.97sec. There'll be 900 of these coupe SVJs - SV for Super Veloce, J for the chapter of the same letter in olde-worlde motorsport regulations which outlined the measures a carmaker must take to homologate racing sports cars.

The Aventador isn't the focus of Lamborghini's race efforts, but by the yelp the SVJ makes from its 6.5-litre, naturally-aspirated V12, you wouldn't know it.

Power is up by 20hp over the Aventador SV to 770hp, developed at 8,500rpm on the way to an 8,700rpm red line. But that's not even the half of it: the reduced internal friction, lightened flywheel, titanium inlet valves, port-injector rail relocation to within the cylinder head, and easier breathing exhaust, have also liberated more torque right throughout the rev range. The Aventador SV made its peak torque at 5,250rpm, where the SVJ is already making more, but its peak of 531lb ft doesn't arrive until 6,750rpm, and at that point it doesn't fall away as rapidly as in the SV. So it gets going sooner, and keeps going longer.

That's only one thread of the SVJ's development. The next biggest news is the adoption of the ALA (Aerodinamica Lamborghini Attiva) active aerodynamic setup which received its debut in the Huracan Performante, but is here in V2.0. It makes 40 per cent more downforce than an Aventador SV with a tiny reduction in drag, and features vents to stall splitters/wings at both front and rear of the car.

At the back, a central pillar channels air out of the engine bay, through the hollow rear wing and out of its underside, turbulently, to stall one side of the rear wing or the other, or both, by breaking the laminar flow underneath it. (Hard to explain in words, easier in a sketch.)

Thus it reduces drag and downforce in one go, increasing acceleration and top speed. In cornering, its tendency is to keep downforce on the inside of the car, which helps keep the car flatter and increases turn-in. "Wouldn't it just be better to make downforce across the entire wing?" I asked. "Sort of but not actually," comes the answer, almost convincingly: if the car was only RWD, maybe it would, but ALA allows a shallower steering angle and makes for a quicker initial turn, so power can be distributed to the front earlier and the SVJ driven out of a bend more quickly. It's confidence giving and could be worth 1-3sec a lap on the Nordschleife, they say.

Acts III and IV are a weight-shaving regime, although this is a big car that's already predominantly carbonfibre, so expect the 1,525kg dry weight to be comfortably over 1,700kg with fluids at the kerb. The chassis gets stiffer anti-roll bars and dampers, springs that are the same (though with a stiffer effective rate because the body is lighter), and tweaked software for the 4WD system and the active rear-steer tech which first arrived on the Aventador S. As in a Ferrari, one ECU talks to and controls the lot.

And then lastly there are the tyres: thus far, Aventadors have been fitted with Pirelli P Zero Corsas. The SVJ gets optional Trofeos, the race-derived compound that gives the SVJ the biggest lap time advantage of all, probably contributing 10 seconds around the Nordschleife. Although Lamborghini is, quite reasonably, reluctant to split these things up into 'this is worth, that is worth...' because they all contribute together.

We tested the car on Corsas, for a complicated but sensible reason: Trofeos tend to wear quickly under repeated hard conditions on abrasive surfaces, so Lamborghini recced Estoril race circuit a few weeks ago, and decided it would bring the harder-wearing Corsa tyres, and then 240 sets of them, so it needn't perform more than one tyre change a day. On returning for the actual event, though, they found the circuit had been resurfaced with asphalt so smooth that you could run an SVJ around on Blu-Tack for a fortnight and it still wouldn't wear it out. It's at once both a hilariously and frustratingly squealy low-grip surface. The inherent handling balance of the SVJ, though, is unchanged, says Lamborghini - unless you give the car a low-speed 'bung', in which the car will understeer where it would normally tuck in.

We get not many laps, during which it quickly becomes apparent that in 'Strada' or 'Sport' mode the single-clutch automated manual gearbox's shift isn't up to a 770hp naturally-aspirated engine's response, so the car needs to be in 'Corsa', in which it bangs shifts through in actually quite satisfying fashion. So long as you're at absolute full throttle, that is.

If you are, you'll need to be on quite a large race track, because the SVJ is ridiculously fast. Oh, I'm sure there are more efficient and more worthy engines, but strap a 6.5-litre, naturally aspirated V12 that revs to all-but 9,000rpm to my back and I'm a pretty happy camper. I'll say it: it's the greatest engine in production. Yes, I know it does 14.4mpg and emits 452g/km. For once, I don't care.

Because nobody else quite does this, you know? Sure, there are n/a Super GT cars, one from Maranello with more power even than this, remarkably, but the way this yelps as it whips past its 8,500rpm power peak, and is so intolerably loud, and yet so smooth and linear that you can bang into the limiter without really realising, really is unique. Because of the 14.4mpg thing, probably.

Hybridisation is where it's at, next time around, for whatever the Aventador becomes when it's replaced in a few years, which will give Lamborghini problems, because motors and batteries add weight, and it'll need 4WD, still have a V12, maybe get a better, heavier gearbox, which means it'll need other gubbins to try and disguise the mass. The SVJ's four-wheel-steer system and the ALA airflow vectoring is exactly that kind of gubbin. And they work, to a point, resulting in an immensely capable - hence that laptime - but also slightly unusual car to drive.

Take locked-down body control and mammoth grip and traction as read. Braking is excellent too. The oddness comes at the heart of a corner. Not unlike Ferrari's F12 tdf, and some other active rear-steer cars, the SVJ feels like it's second guessing you. As you turn, it's fairly common on circuit to keep a brake pedal lightly trailed towards the apex, but do so in an SVJ and the active-rear steer (and ALA, presumably) act together too, to disconcertingly whip the car towards the apex. Any kind of playing with the throttle mid-corner can do likewise. So, a bit like the tdf, or early McLaren 12Cs, you kinda have to drive the SVJ its way. The brake lights on the instructor's SVJ I'm following (he's there to make sure I don't bin it), go out before he's turned-in. So I try the same, and I think that's the answer: rear-steer does what you'd try to do yourself, pulling the car towards the corner. It leaves you to make smaller inputs, but, unusually, be on at least steady throttle before an apex.

On the way out, in Corsa mode, things are pretty neutral, even with some lock still applied and the throttle full down. In Sport it's apparently more rear-biased, but I didn't get a lot of time to try it. If you unsettle the car on the way in, certainly there's still a natural adjustability there, but the Aventador has always been an unexpectedly docile car given its size and potency. I think that character is still in there, somewhere.

Thing is, I get out of it wanting to find out, rather than just relieved to hand the keys back and walk away, sweating. Which, given the power, where the engine lies and how fast it can go, is quite a feat in itself. It's an unusual prospect, but a unique car and, ultimately, a rewarding and rather breathtaking one.



SPECIFICATION - LAMBORGHINI AVENTADOR SVJ

Engine: 6,498cc V12, petrol

Transmission: Seven-speed ISR, all-wheel drive

Power (hp): 770@8,500rpm

Torque (lb ft): 531@6,750rpm

0-62mph 2.8sec

Top speed: 217mph

Weight: 1525kg

MPG: 14.4mpg

CO2: 452g/km

Price: £360,000