Speed on top for Red Bull at Barcelona.
With Renault, Toyota, McLaren and BAR already busy testing in France ahead of the Bahrain Grand Prix next weekend, today [Thursday] saw Williams join Red Bull Racing at Barcelona.
Red Bull junior driver Scott Speed concluded two days of running at the Circuit de Catalunya for the Milton Keynes based team by topping the timesheets ahead of the more experienced Williams pairing of Nick Heidfeld and Antonio Pizzonia.

With Renault, Toyota, McLaren and BAR already busy testing in France ahead of the Bahrain Grand Prix next weekend, today [Thursday] saw Williams join Red Bull Racing at Barcelona.
Red Bull junior driver Scott Speed concluded two days of running at the Circuit de Catalunya for the Milton Keynes based team by topping the timesheets ahead of the more experienced Williams pairing of Nick Heidfeld and Antonio Pizzonia.
Speed, who will compete in the new GP2 series this season, was making his debut in a Formula One car, but it didn't stop the American from going half a second quicker than Heidfeld in what was also his first run at the Spanish circuit.
"The car is definitely the most powerful car I've ever driven," he said. "This test all went smoothly with no dramas. My first impression was wow! The braking power particularly impressed me. I really enjoyed myself and it was very productive, as the 68 laps I completed have qualified me for a Superlicense and I've now learnt a track that I will be racing on later in the year. I found all the data analysis side fascinating and felt fine at theend of the test, having trained real hard for this."
Williams spent the first day of its two day test session in Barcelona preparing for the upcoming Bahrain Grand Prix with Heidfeld focusing on longer runs in the FW27 and Pizzonia working on practice starts.
"We're back in Barcelona for just two days this week, testing parts in preparation for next weekend's race in Bahrain," test team manager Tim Newton explained. "With Nick and Antonio on duty for the team, we concentrated on the usual set-up work this morning. While Nick carried out a series of long runs this afternoon, Antonio put the FW27 through its paces practising starts. Both drivers will return to the track tomorrow."
Behind the two Williams, Neel Jani was also drafted in by Red Bull for the test, although his quickest lap time was almost two seconds down on that of Speed. With the team focusing on engine work and not needing the services of David Coulthard, Christian Klien or Vitantonio Liuzzi, sporting director Christian Horner said he felt it had given the team chance to blood some of its young guns.
"The technical programme centred on engine work, for future development of the Cosworth V10 and did not require our regular race drivers," he said. "Therefore this seemed like the ideal opportunity to introduce Neel and Scott to Formula One, as part of the Red Bull Junior programme.
"Both drivers did a good job, making no mistakes. Given that Scott had never driven a Formula One car before, he put in a solid drive getting used to all the extra horsepower. Neel also had to contend with a damp track on the final morning, before running in the dry in the afternoon and he provided valuable feedback to our engineers."
Leading performances (24 March) - Barcelona:
1. Scott Speed Red Bull-Cosworth 1min 16.123secs
2. Nick Heidfeld Williams-BMW 1min 16.677secs
3. Antonio Pizzonia Williams-BMW 1min 17.177secs
4. Neel Jani Red Bull-Cosworth 1min 18.026secs
[all cars on Michelin tyres]
Weather/Track conditions: Mild, mixed
All times unofficial - courtesy of BMW Williams