"It has nothing to do with grip, grip level or downforce level, it's more getting the entire car to work as a whole. I think that's where we're trying to understand and improve."
The other team that could be a factor this weekend is a resurgent Ferrari, which is still riding high off Fernando Alonso's surprise victory at the Malaysian GP.
The Ferrari team had looked to be in crisis following a poor offseason and the continuing struggles of Alonso's teammate, Felipe Massa, who has yet to finish in the top 10 this season. There has been speculation the team is preparing to fire him, with Sauber driver Sergio Perez being named as a possible replacement.
Alonso tried to play down the team's chances in Shanghai, saying his victory at Sepang had as much to do with luck as it did strategy.
"It's always a factor that we always seem to forget is there," he said. "I remember in Australia we had a great team effort from everybody there, a good strategy, pit stops, etc., but we also had some luck to get the fifth result and in Malaysia we had the same."
Alonso may also be hoping for weekend storms after driving so skillfully in the tropical downpours in Malaysia.
"In a wet race, we can lose a couple of points or we can win a lot more," he said. "Maybe the risk of a wet race can be good for us at the moment because in normal conditions, we are not as fast as we expected."