Toro Rosso have arrived at Barcelona for the final pre-season test with an "almost completely brand new" STR10.
The team returned to the Spanish track on Thursdaywith Carlos Sainz Jr putting in the laps and it was immediately apparent that the STR10 had undergone changes.
The most notable of these is to the nose, which is more in line with the Williams design, while there have also been other changes to the car's aerodynamics.
In fact Toro Rosso technical director James Key says the car is "almost completely" brand new.
"The car itself is radically different here, so we have to start again [in terms of set-up]," he told Autosport.
"It's almost completely brand new: Aero, cooling, suspension and the nose is new, it's a Williams direction.
"We always knew this was the way to go – the only reason we did the long one was because this [new nose] is technically more difficult with the impact test, and we wanted to give ourselves a banker.
"We got the long one neutral in terms of aero performance, but that's all it was. It basically means you can run without having the stress of squeezing through a difficult impact test, but this one has passed pretty well.
"This and the rest of the car is actually the 'real' racecar. Everything before that was [built] months ago in terms of aero."