Aluminum and stainless steel are too far apart on the galvanic corrosion scale and should not be used together. Stainless steel treated with a plated coating would be acceptable.
I'll leave that to you and maxcichon to argue about.
I'm just going by what Max tells me ( and gives me ), he knows about this stuff as part of his job.
I'm a computer guy and weekend mechanic, not a metallurgist.
Besides, my engine does not get wet. Ever.