Kubica: F1.08 harder to drive

The Pole driver also reckons some of the problems with the new car are likely to take quite some time to be solved.

"There are a couple of things that have been improved a lot but there are some issues still that I think will not be easy to fix, but of course the car is performing better," said Kubica.

"I think half the problem is gone but the other half is there, and we cannot fix it quickly, so we are trying to balance the car as is.

"It is not easy to balance, in the windy conditions I think last year's car was easier to drive and set up than this year's car."

The team had a difficult start to testing with the F1.08, with balance issues hindering their progress before the situation improved.

Kubica admits it is hard to predict how competitive the team will be when the season starts in Melbourne.

"It is difficult to judge," he added. "It's difficult to compare but I think as the previous tests we are not working on the competitiveness, just trying to do our best, get the best from our car and try to learn new things."

"Of course we are getting better and from the driving point of view I am expecting more and more. There were a couple of things that were very positive, especially on the mechanical side, which made our car quicker and easier to drive and that is very positive."