I'm considering a bra for my FR3 30 DS also...
The front nose of this thing is gel coat like a boat... there is no paint on it, so I think it would be ok... the decals could see a little wear possibly from the buffering going on.
I used bras on my cars for years and I always put a couple of coats of wax on before installing them so I never noticed any problems....
A bra will keep the rock chips to a minimum, but bugs are still going to be an issue up high....
2015 FR3 30 DS
Days Camped 28