Sebastian Vettel expects to have a clearer understanding of the RB8 car he will begin the defence his double world crown with when Red Bull fits a major update package to a new chassis for team-mate Mark Webber to drive at Barcelona on Saturday.
Amid speculation that several new teams will put the final upgrades on their cars prior to the Australian Grand Prix opener at Melbourne in a fortnight's time, Vettel insisted that it would still be difficult to accurately define the pecking order before the first race.
"We have some new bits for the next two days and then we'll know a little bit more," he said. "Everyone is a bit in the same situation. Usually the last couple of days of testing are quite important because you bring some new bits and the car is closer to what you will race at the first race, so we will see if that comes true.
"Hopefully we can make another small step forward and then we should be okay.
"I think other people will as well, but still it is a bit difficult to judge whether you are really quick or not because people play around with the fuel loads and the tyres. The time of day makes a big difference as well so it's hard to really judge it. I think we'll know more than now in Australia."
Vettel endured a fractured day's running on Friday and was forced to stop on track for an unspecified problem, but said that he remained happy with progress after ending up third in the times, some 0.7s off Romain Grosjean's ultimate pace.
"So far testing has been quite good for us, not perfect," he said. "Surely we had you know some bits here and there failing and some bits that we need to sort out but all in all I feel happy.
"It was quite a messy day in terms of finding the rhythm because we had a lot of red flags out there today but we didn't have a big problem.
"We stopped on the circuit, but fortunately at a spot where there were not that many photographers at the time, so that was good! It's never nice to stop, but we brought the car back and it wasn't a big problem and after lunch we went back out and I think we did more or less what we wanted to do.
"Obviously we always want more at the end of the day so we didn't fulfil the programme entirely but I think we ended it on a good way.
"It's good to have another day in the car today and I have another one on Sunday which is a good feeling," he added. "It's good to know that in two weeks we are going racing again. I can't wait really to get down under."