Sauber duo Sergio Perez and Kamui Kobayashi have had seat fittings in their team's new C30 ahead of its official launch in late January.
The Ferrari-powered car is the first one that will have been penned by new technical director James Key, who joined the outfit in the early stages of the 2010 campaign.
Key played a pivotal role in helping overcome early-season reliability problems and deliver improved competitiveness over the rest of the year.
Perez, who had his first test for the team in Abu Dhabi in November, got his first view of Sauber's 2011 car on Tuesday, with Kamui Kobayashi heading to the factory on Wednesday.
Although Perez is returning home to Mexico for the Christmas holidays, he will move to Switzerland in early January so he can be close to the team's Hinwil base.
Sauber is due to launch is C30 at Valencia on January 31, on the eve of the first official F1 test of the season.