I am not a big fan of stainless, sometime it can be very brittle. I think some copper grease on them is my plan.
I’m not either. It’s much weaker, likes to gall, greasy to drill. I like it for trim, but always try to avoid where real strength is involved.
I would never use stainless fasteners in a safety-critical application, unless designed for them. Likewise stainless steel brake lines.
I’ll be using Evans to avoid corrosion, just like all my other cars have.
I would hardly say that intake manifold studs are “safety-critical” nor is great strength required in this instance. I’m a big fan of stainless (except in high-strength areas like suspension, steering & brakes). No corrosion, and always knowing you can get things undone make stainless a win win for me. I always use Copaslip, too.