Toro Rosso has emerged as one of the last teams on the Formula One grid to unveil their new challenger for the 2009 season. After undergoing its initial shake-down run in Italy last week, the new STR4 is now participating in the last group test session in Barcelona before the start of the season. As in years past, Toro Rosso's car looks virtually identical to that of its senior team Red Bull Racing. However, while the design was carried out by Red Bull's Adrian Newey, Toro Rosso was quick to point out that the car itself has been, for the first time, constructed at STR's headquarters in Faenza, Italy. The team's move towards independent manufacturing (instead of joint development with Red Bull Racing) promises to help the team adapt to the ban on customer cars that takes effect next year, while simultaneously making it a more attractive stand-alone unit for a future buyer. The STR4 employs a Ferrari customer engine instead of the RB5's Renault unit, resulting in a different fuel tank and employing Ferrari's KERS regenerative braking system, which, when joined by the fine-tuning towards STR's drivers, makes for a vastly different car than its Red Bull counterpart, according to Toro Rosso. With Sebastian Vettel â€“ who took the team's first victory last year at Monza â€“ starting for Red Bull Racing this season, the STR4 will be piloted by Sebastien Bourdais and newcomer Sebastian Buemi.