Looks like Vettel & Webber swapped cars - Spanish Grand Prix P1

RED BULL

It was another business usual day for redbull with a small change. Last year’s Spanish Grand Prix winner and pole sitter was the fastest man around the track in the first practice session today.During the session he had to pit after developing a problem with a sensor on the car, and was later told not to use his Kinetic Energy Recovery System
Sebastian Vettel has once again been asked not to use KERS, the single chink in Red Bull's Adrian Newey designed armour
Webber and Vettel were trying out the latest developments that Red Bull hope will keep them clear of the competition.

They had a new floor, as well as new wheel rims, following a design principle pioneered by Ferrari that enhances the airflow in that area.

Webber's best lap was a one minute 25.142 seconds, which was 1.007secs quicker than Vettel as the two drivers ran different programmes.

But it was not a totally seamless morning for the world champions

MERCEDES

The closest car to the flying RB7s was Nico Rosberg’s Mercedes on a 1’26.379.Michael Schumacher was seventh in the second Mercedes in 1m 27.016s

FERRARI

Fernando Alonso was fourth fastest ahead of Sauber Sergio Perez, who improved to fifth with a late effort of 1’26.738.

MCLAREN MERCEDES

The fastest McLaren driver was Lewis Hamilton on a 1’26.988
Force India tested a revised aerodynamic package on the VJM04. Adrian Sutil ran an upgraded car and reserve driver Nico Hülkenberg used the previous specification for comparison

enson Button was doing a constant speed aero test, he was trying out this new McLaren front wing, which has strakes underneath it.

"They were putting visibility paint on it. They'll take photos of the patterns the airflow creates and send them back to the factory for analysis."

Button reported an improvement to the car's rear stability.

Hamilton set his best time early in the session and spent the best part of an hour in the pits while the mechanics fixed a problem with his car. He made it back out on to the track with only two minutes to go.

RENAULT - LOTUS

The teams were trying new parts they hope will raise their competitiveness.
But their work was made more difficult by a slippery track and a strong wind, and many drivers complained about a lack of grip - so much so that Renault's Vitaly Petrov told his engineers his tyres were "like ice".Petrov was saying that the new Pirelli hard tyres are difficult to warm up

Williams

Williams are hoping this weekend will bring them the first points of the season after the worst start to a year in their history.They have a raft of new parts here, including new wings and an exhaust-blown diffuser and they received something of a boost when veteran Rubens Barrichello, who was trying out the developments, finished the first session 10th fastest
Despite that, there were relatively few off-track incidents, although Williams rookie Pastor Maldonado continued his torrid debut season with a spin into the barriers at Turn 13.
Maldonado lost control through the corner, sliding wide onto the slippery outside of the track, where he was unable to stop the car continuing into the gravel trap and barrier

PIRELLI (TYRE PROVIDERS)
All the teams spent the session on the harder of the two tyre options - Pirelli has brought a new, more durable, version of its 'hard' tyre to Barcelona in response to the track's notoriously abrasive surface.

Source : BBCF1, Fanatic, Tweets from Twitter, F1.com, Scrabs F1