I have retired from surveying as of a few months ago, (still cleaning up, and taking on small work) it's doubtful I will ever use my 450i in the situation that I destroyed the skid plates
in general, I am very conscious of how I pass over bumps, rocks, stumps, etc, rarely ever bottom out, and when I do, it's on the edge rail one side or the other, I don't rail thru the trails like some guys on sport machines
I do however get sticks, branches, etc that get caught and drag or poke up ( in my current condition with about 50% skid plate coverage) When I'm using it for firewood logging, after a tree is dropped, and limbed, lotsa times I drive thru the slash, this is my biggest need for underbody protection, I don't think rails would work