“I want to see how the diffuser works before we spend that much money,” said Toro Rosso boss Franz Tost regarding the double diffuser.
Although not quite visible in Monaco – where the level of downforce was not particularly high, the Red Bull RB5s did great during last weekend's Turkish Grand Prix. Sebastian Vettel clinched his and his team's second pole position of the year, while both drivers managed to climb the podium at the end of the Sunday race.
However, as revealed by rookie driver Sebastien Buemi, it seems the implementation of a new rear diffuser into the STR3 will also interfere with the car's initial structure, as the single-seater's design is not compliant with the new element. As in Red Bull's case – where designer Adrian Newey took almost one-and-a-half months to integrate the diffuser into the RB5 – Toro Rosso will have to redevelop the entire rear fascia of their car in order to debut the feature.
In case Tost does decide to spend some of his team's money on the double diffuser – and we don't see a reason why he shouldn't do that – it would take at least two grands prix to debut the new feature. Realistically speaking, the Hungarian GP seems the most likely target for STR.