But it is the feel of the thing that makes the GT3 such a spectacularly enjoyable car to drive (even more so in RS trim). Personally I think it has one of the best steering systems of any car on sale today - feelsome, accurate and with ideal weighting, whatever the corner speed.
Does it steer and more sweetly than the regular GT3? Without driving the two back-to-back on the same road it is difficult to be categorical, but from where I’m sitting today I’d say so. There’s just a fraction more feel and confidence and feel on turn-in, especially through the faster stuff.
At 1370kg, the RS saves 25kg over the GT3. Why not more? Because the weight-saving measures have to first clawback the mass added by the extra bodywork and wider wheels; the RS runs an extra 10mm on the front and 20mm on the rear.
To get down to that weight involves careful options selection, though, because you need to do without air-con (20kg) and the stereo (6kg), and fork out for ceramic brakes (20kg), and the lightweight bucket seats (not cheap, at £3064). Do all this and you’ll have the exact specification of GT3 RS shown here.
For the truly committed, doing away with the bi-xenon headlamps saves a further 6kg, while an optional lithium-ion battery sheds 10kg.
So on the occasions when it’s possible to use everything the 3.8-litre motorsport engine has to offer, does 15bhp make a difference? On paper the RS is more accelerative than the GT3, but only fractionally (there’s just 0.1sec in it from rest to 100mph).
In reality you’d be hard pushed to tell the two apart in pure performance, but in character they perform slightly differently. The extra power comes not as a result of changes to the engine internals, but a more efficient induction kit and higher compression ratio.
The flipside is that the maximum torque, although identical, is produced at higher revs in the RS. So you have to work a little harder for the performance. But the payoffs are greater, because over the final 1000rpm the RS sings that little bit more sweetly.
To balance the additional drag produced by the RS’s overdeveloped aero package (which produces 170kg of downforce at 186mph, or around double that of the GT3), Porsche has dropped the standard gear ratios.
In doing so Porsche has, perhaps inadvertently, solved one of the regular GT3’s main drawbacks as a road car: exceptionally long gearing. Second is still good for 77mph and third 106mph, but presented with a temptingly brilliant road, you end up using more of the rev range and more ratios.
The grip levels are so high that realistically, on the road, you’re only ever going to get near the limit through the tightest turns. But do so, and contary to what you might expect, the RS proves easier to manage than the regular car.
Because you have more front-end grip, it feels better balanced, with less understeer and more neutrality. And because the RS gets Porsche’s clever active engine mounts as standard, it better controls the mass of the engine and gearbox (270kg) in direction changes.
Dynamically there is only one grumble: that the height of the brake pedal, combined with the effectiveness of PCCB (Porsche Carbon Ceramic Brakes), makes heel-and-toeing tricky at road speeds.
It would be easy to dismiss the GT3 RS as a trackday irrelevance. Many will be used as just that, their owners able to tinker with the infinitely adjustable suspension settings.
But the surprise here is that the GT3 RS is still a useable road car, and not by virtue of conceding just enough comfort and forgiveness to get by, but because it is genuinely enjoyable and engaging to drive. The ride is hardly any less supple than the regular GT3, the firmer suspension counterbalanced against taller sidewalls.
Is it worth a £20k premium? We are into a diminishing margin of returns here. The regular GT3 is hardly what you’d call disappointing, and the premium represents another 25 percent again. But if you can afford the extra, the RS is even better.