Red Bull's Sebastian Vettel topped the timesheets at Jerez today, as the Milton Keynes outfit, along with BMW and Williams, brought its 2008 programme to an end.

The German was once again partnered by Sebastien Buemi as both drivers worked on evaluating various mechanical set-up changes in conjunction with the 2009 specification slick tyres.

The RB4s ran reliably all day and overnight work on Vettel's car meant it was more to his liking today, allowing the Austrian outfit to leave Spain with a good understanding of next season's rubber.

"We've had pretty smooth running at this test and have completed a lot of mileage before the end of the year," said the German. "I think we've done everything we could here, learning about the tyres and next year's regulations and hopefully we will start next year with a car strong enough to challenge the big boys."

BMW continued with its two interim cars, based on the 2008 chassis with 2009-spec bodywork. This week's test saw the team come as close as could be to the maximum test mileage and tyre allocation under the 2008 testing regulations..

In the morning, Christian Klien drove the KERS' equipped F1.08B. Working on different energy strategies, the team continued the development work as scheduled. "We made good progress today," said the Austrian. "We still have a lot of work to do on the KERS system. But the promising test results show we are moving in the right direction."

Robert Kubica in the sister car, but without KERS, tried numerous set-up solutions aiming to improve on the results from using the new slick tyres. For the afternoon session, according to the plan, he switched to the KERS' equipped car, but due to a mechanical failure he had to abandon the scheduled programme. Kubica then got back into the conventional F1.08B and continued testing for the rest of the day.

The busiest man today was Kazuki Nakajima in the Williams, the Japanese driver completing 131 laps as the Grove outfit concentrated on set-up work, aero optimisation and slick tyre development.

"These two days at Jerez have been really productive," said the Japanese driver. "Unlike last week when the weather was quite bad, I've covered a lot of mileage with the car which was good for me as it's allowed me to get used to all the changes. In terms of what we've been testing, we've worked on set-up and the aero package for next year, but we mainly concentrated on the slick tyres this week. It is quite interesting to drive on slicks."