My opinion is road salt is gonna get in there no matter what you do to stop it, unless you get some sort of spray on coating. Random stones (I assume you mean on roads and not on trails) shouldn't be big enough to cause any damage to your undercarriage, or else cars, which have even lower ground clearance, would be in real trouble. Not only that, but the extra weight of these is only worth it if you actually use them off-road to stop from breaking stuff thats costs $$$ to fix...