Yes, here it is - the worst-kept secret of 2011: the new 493bhp Porsche 911 GT3 RS 4.0. But who cares about the leaky Porsche information machine when the company gives us what is effectively a GT3 RS with an RSR motor out back.

It will come as a disappointment to those hoping for a full-spec RSR for the road that this car was never meant to be anything more than an engine exercise. Yes, there are some notable tweaks in other areas, but the significant change is the motor.

This has been stroked to 80.4mm (from 76.4mm) because the bore is already at it limits. Inside, pretty much everything is different, with the crowning glory being the crankshaft from the £300,000 racing RSR. Power is 500PS (493bhp in old money) and torque is now 341lb ft. Increases over the 3.8 are 23lb ft and 49bhp. And this is finally an RS with something to look at in the engine bay, even if it is just a pair of reddish intake filters lurking in a carbon surround. The transmission is the same - yes, the rumours of PDK were nonsense - but the clutch has been strengthened.

YouTube - New Porsche 911 GT3 RS 4.0 - evo Magazine EXCLUSIVE!

The chassis has benefited from lessons learned in the GT2 RS project, and the RS 4.0 runs the same helper spring at the rear, uni-ball joints on the lower-rear arms (the tops remain rubber) and new spring and damper rates. The aim is an even more precise chassis than the 3.8’s.

The rest of the car is existing, extra-cost items from previous RSs. The expensive plastic front wings with integrated wheel-flares are standard, as is the GT2 RS’s carbon bonnet. The rear screen and rear side windows are plastic, leaving a weight of 1370kg – only 10kg less than the old RS, but combined with that extra slug of power it gives the RS 4.0 a power-to-weight ratio of 365bhp per ton versus 329 for the 3.8.

Standard colours are white or black, the wheels are painted white, and a new sticker-set leaves no-one unsure of the swept capacity of your new 911. Inside there are 4-litre logos everywhere, and a new steering wheel, which is the metal-covered PDK wheel from the Turbo, but minus the paddle-shifters.

Lastly, the aero package has been upgraded with a pair of front dive-planes that provide enough additional downforce at speed to warrant the rear wing being set with extra rake.

The UK list price is yet to be confirmed, but Porsche has advised that £128,000 is likely to be the figure. There are only 600 cars being built, and fewer than 50 will come to the UK.