Adrian Sutil had a smooth ride with the seamless shift gearbox but the German struggled for balance on slick tyres as he brought Force India's three-day test here to a fruitful end.
A minor mechanical problem, which caused a little downtime, was the only glitch as Sutil ran 72 laps with at a dry and sunny Jerez de la Frontera circuit posting his best lap at 1min 19.965.
Though happy with his experience with the new gearbox, Sutil felt that there were certain issues which he needed to work on.
"I was very happy with the balance of the car and enjoyed testing the seamless shift box for the first time. We had a few small problems towards the middle of the day, but overall it felt good and it seemed like a step forward," Sutil said.
"When we got going again in the afternoon, we tried the slick tyres and, although I enjoyed trying them out again, we couldn't seem to get a good balance with them. There's quite a lot of work still to do before 2009, but then we still have time to get it right," he added.
The team will now return to its Silverstone headquarters before heading over to Hungary next week for the 11th event of the Formula One World Championship.