stainless steel lug nuts

You never use stainless nuts or bolts for any "loading" application, like suspension or brakes. I would include lug nuts in that as well. Stainless will fail (pull the threads out very easily) under moderate loads.

For instance, stainless bolts will be used in shear pin applications where you want the bolt to fail before other things are damaged. Alloy Steel is much stronger and will bend a lot before failing.