The next-generation Porsche 911 GT3 RS, seen here testing at the Nürburgring, will be a "far greater step forward" over the current GT3 than the last RS was in comparison with its GT3 stablemate, according to a well-placed source.

As with the previous generation, the new GT3 RS will be both lighter and more powerful than the GT3 on which it is based, in this case the 475bhp, 1505kg  car derived from the current 991 series of 911.

However, the major step forward with the new RS has come with the aerodynamics. An extensive system of wings and spoilers, shown here in spy shots, means the car is already developing levels of downforce that make it "close to a racing car" far ahead of its global debut next year.

Currently the car is testing with a standard GT3 engine, but the RS is said to have an output of "at least 500bhp", eclipsing even the 493bhp of the 4.0-litre, limited-edition Porsche GT3 RS 4.0, which will make it the most powerful naturally aspirated six-cylinder road car engine produced by Porsche to date.

Additionally, Porsche has reworked the GT3’s suspension and fitted the wheels and tyres from the 918 Spyder, improving grip and traction.

Purists might have been hoping that the RS would provide an excuse to return  to a manual gearbox in the GT3, but it seems it will feature a seven-speed dual-clutch automatic like the existing car, although bespoke ratios are a possibility.

Given that the GT3 can hit 62mph from rest in a claimed 3.5sec, the lighter, more powerful RS should reduce this to the region of 3.2 or 3.3sec.

However, due to the added drag of its aerodynamic addenda, top speed is unlikely to increase beyond the GT3’s 196mph and might even be reduced.

Official pricing and details have yet to be released. The current GT3, however, costs £100,540.