I have some experience of stainless fixings and the impossibility of their removal from alloy after exposure to weathering, or worse still salt water, having maintained a sail boat for a few decades....However, when I typed of Kevin`s decision to utilise SS fasteners where possible on what at the time was his +8 is relative to the effect thereof after 20+ years, although perhaps only having covered a tad under 30k miles in that time, some of which was on salted roads with snow and ice around.
Bottom line, as I typed above the stainless fixings holding the steel tubular exhaust manifold to the alloy of my +8 head, having never been disturbed since Kevin had initially rebuilt the Mog 20 years previously, unscrewed without issue, which is a world away from my expectations relative to any and all exhaust fixings on my Porsche 991.1 at 10 years old and circa 43k miles...
The nuts and bolts Kevin chose to hold on my Mogs exh flanges together were also SS, and a couple or so years back when both two into one mild steel sections of the exhaust were past their best I was grateful for Kevin`s use of SS fixings which made replacing those two sections of exhaust so much easier...Such was the condition of the fixings I removed in the task, that I was happy to reuse them.
Kevin also utilised SS fixings to mount the wings, and some time back I also decided to unscrew a few of them to ensure that their removal and replacement would be a relatively simple process which it was, and I again re-used the same fixings. I think I posted a pic of the wing fixing and the surrounding area for those seeking to make comparisons with the look/effect of SS against their own wing fixings.
There are different grades of stainless steel and it is not suitable for all tasks as Howard has wisely pointed out
I am no metallurgist and type only of my personal experience relative to my +8, in the hope it might advantage any fellow owner.
I have spent a few decades struggling with the effects of corroded fixings, thus I also well appreciate just how rewarding and time saving and FAR simpler a task can be made, if one can put a spanner to a nut or bolt and it with a degree of confidence and to find that loosens off just as it should...