Felipe Massa has driven the ultra-exclusive Ferrari 599X, a hardcore track-focused version of Ferrari's 599 Fiorano.
The 599XX replaced the FXX this year, and the programme runs along similar lines, with customers giving feedback to Ferrari engineers that is then used in the development of future road cars.
Massa drove the car at Valencia. After several laps he said: "I really enjoyed testing this car, I think it's extremely powerful and has an exceptional stability. Considering that it has been planned for the track it's really easy to drive."
The Ferrari 599XX gets a retuned version of the 599's V12 engine, with its rev limit boosted to 9000rpm and its weight reduced by the adoption of a new crankshaft and more extensive use of carbonfibre in ancillary parts. Ferrari says it "achieved its goal" of just under 700bhp at 9000rpm.
The power is transmitted through a new version of Ferrari's robotised manual gearbox that features shift times of just 60ms. Ferrari claims that the 599XX can lap its Fiorano test track in 1m 17sec, less than a second off the time of the Enzo-based FXX that it will replace.
The most obvious external alterations to the regular 599 are a variety of carbonfibre additions, including a small roof spoiler, carbonfibre brake disc covers and a enormous carbonfibre undertray and rear diffuser.
Inside, the cabin has been stripped out to race specification, with a bare dashboard and carbonfibre cladding. It does feature a display screen, however; it's used by Ferrari's 'virtual car engineer', which provides instantaneous data on the vehicle's efficiency.