Before we get into the nuts and bolts of this last and loudest laugh of the 996/997 series of Porsche 911s, you should know its run of 600 units is dictated not by demand, but that thereafter its parts supplies will dry up; and at a price of £128,466, Porsche will make no money from any of them.

Think about that. What you are looking at is the greatest version of the greatest sports car ever built. Porsche knows it could have made thousands and charged half as much again for everyone. But it chose not to.

Instead it is what Porsche calls a ‘thank-you’ to its most loyal customers, the only people with a hope in hell of getting a sniff of one. Most will have already owned at least three GT3s.

What those loyal customers will find is so much more than a standard GT3 RS with a bit more poke. Instead it is a heady confection of Porsche’s most extreme road car, the GT2 RS, and its all-conquering racers, the GT3R and RSR.

Update: The new lightweight, 'purist's' Porsche 911 R revealed at 2016 Geneva Motorshow

The Rose-jointed rear suspension with its helper springs is pure GT2 RS, the engine courtesy of the race cars, their long-throw crankshaft stroking the unit out to 3996cc, making this the largest engine ever to sit in the boot of a Porsche.

A new suspension tune has been achieved thanks to bespoke spring rates, but much of the car, including the gearbox, its ratios, the steering, brakes and tyres are carried over from the ‘normal’ GT3 RS. Myriad weight saving measures including the carbon bonnet and front bumper from the GT2 RS, meaning a base-spec car wearing optional ceramic brakes weighs just 1360kg, about 10kg less than a 3.8-litre RS.

A new aero pack provides more downforce than any previous RS, those natty front winglets essential to balance the extra rear grip provided by that new rear wing with its 9-degree angle.

The result? The car we named last year’s best driver’s car in Britain, the 3.8 GT3 RS, has not been made to stand aside. It’s been blown off the road.

Look at the stats like the 0.1sec knocked off the 0-60mph time and it’s hard to see why. But drive the 4.0 RS and it’s blindingly obvious. Despite it’s extra 50bhp, it’s not the power you notice, nor even its additional 22lb ft of torque. It’s where that torque is that makes all the difference.

2016 Geneva Motorshow update: Porsche confirm next generation 911 GT3 will be built with a manual gearbox

One fault common to all GT3s is their unorthodox blend of a peaky engine and wide gear ratios. With the new motor, those gears finally make sense. On the road you can just park it in fourth gear and go anywhere from shopping to prison. On the track you have to rewrite your mental circuit notes because almost every corner is now a gear higher. It’s faster, yet easier.

Its composure in fast turns something you’d not credit a car with a tax disc, yet even if you turn off all the electronics it remains fundamentally forgiving, something you’d never say about the more expensive, flawed and less-enjoyable GT2 RS.

Is it perfect? That car has still yet to be built and you’ll find the 4.0 RS keen to understeer in slow corners and its ride merely impressive rather than exemplary over the worst British B-roads.

Ask if there is a car on sale today I’d rather drive on a combination of road and track over the course of the next 20 years and I’ll tell you that if there is, I haven’t driven it.

Porsche 911 GT3 RS 4.0

Price £128,466; Top speed 193mph; 0-62mph 3.9sec; Economy 20.1mpg; CO2 326g/km; Kerb weight 1360kg; Engine 6cyls, horizontally opposed, 3996cc, petrol; Power 493bhp at 8250rpm; 
Torque 339lb ft at 5750rpm; Gearbox six-speed manual

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