Sauber technical director James Key is pleased with the way that his team's major upgrade package performed during Friday practice at Suzuka.
The package includes new front and rear wings, as well as brake ducts, turning vanes, sidepod deflectors and floor modifications. There are also mechanical changes to the car.
Key admitted that progress still needs to be made on the car setup, but that fundamentally the car lived up to expectations after Kamui Kobayashi ended this afternoon's session 13th overall, 3.314 seconds off the pace.
"The balance of the car needs improving, but the numbers that we are seeing and the data stacks up to what we expected, which is the most important thing," said Key. "It's so far, so good, but there's certainly work to do this evening to get more out of it.
"We were pretty methodical this morning going through everything to check the effects of what we brought to make sure that there were no hidden issues, but that seemed okay. This afternoon was about working with the package that we have."
Key stressed that the plan had always been to bring this upgrade to Suzuka and that it was not rushed through in response to the team losing sixth place in the constructors' championship to Force India.
"It was always planned to have an update for Suzuka," he said. "We have pushed fairly hard recently because of Force India's good form, but this time last year we set out when the major packages we wanted to introduce would be targeted for and Suzuka was the last major package of the year."
Sergio Perez, who ended the day 15th, just 0.155sec off his teammate, admitted that there was more time to come both from the aero package and himself.
"There is definitely room for improvement from me, and we also have to get the most out of our new aero package," said the Mexican. "The tire degradation on the front was quite big, and we have to improve the balance to cope with that in the race."