The Swiss squad tried a new rear wing in last weekend's Spanish Grand Prix, which was found to be a step forward.
Chief designer Matt Morris believes that the team now has the foundation for continued improvements.
"Yes, we feel so," he told AUTOSPORT when asked if the rear-end stability had improved.
"It shows in our data and also in the drive comments, so that is positive.
"It's always good when you target things, then you bring them and they do what you expect.
"It's a small step but we need to make a further one."
Although Sauber pairing Nico Hulkenberg and Esteban Gutierrez managed only 15th and 16th in qualifying in Spain, Morris is optimistic about the pace of the Sauber C32.
In the race, the car was stronger, with Gutierrez finishing just three tenths of a second off the points and Hulkenberg losing a strong chance of points when he clipped the rear of Jean-Eric Vergne's Scuderia Toro Rosso after what was deemed an unsafe release from a pitstop.
"We have closed our race pace performance to our competitors and even on qualifying performance I don't think we are so far away," said Morris.
"But it's clearly not where we want to be and we need to work hard and put some more performance on the car."
Further upgrades are expected for next weekend's Monaco Grand Prix, with the team continuing to push hard on development.
"We have got a lot of stuff in the pipeline," said Morris.
"We have more parts in design at the moment, so as soon as we can get them made we will be bringing them to the track."
- Sports & Recreation
- Motor Racing
- Esteban Gutierrez
- Nico Hulkenberg