A little know fact regarding Sauber is that following their 1991 World Sports Car Championship campaign, they were due to enter F1 in 1992 as a full works Mercedes entry in 1992. However, in late 1991 Mercedes decided at board level to pull the plug on their plans following poor economic conditions.
Sauber then made a very brave decision of entering anyway on their own and began a years testing in 1992 before entering f1 in 1993. That first race in South Africa was really impressive - far more so than Haas this season.
Some photographic evidence is out there about this and is notable by the Sauber C12 testing with the much wider Good Year tyres that were then narrowed in 1993.
I am interested in learning more about Sauber's testing that year and which circuits they were at and any materials people might have from those tests.