Chrome plating will add approximately .00025/.0005 lb to each sq.in. of surface area plated. You would add somewhere between 1/8 and 1/4 lb to the weight of the swing arm (if I guessed correctly on the size). Also Shotimer could you explain how chrome plating causes parts to be come brittle.
I've had parts chromed and polished and chromed is the way to go!! With polishing, the you have to worry about the elements so there's the upkeep labor. Trust me, polishing foot peg brackets are no fun. With chrome, just spray it with a little glass cleaner, and wipe it off. As for the brittle thing, chroming does not make the part itself brittle, it just that the chrome plating is not real flexible, as long as your not plating any ss lines, you'll be OK. I've had three bikes with chroming with no problems. I even have my shock spring chromed (check attachment). As long as you find a reputable shop, you should be OK. An contrary to popular belief, chroming does not add a lot of weight.