I dont think it adds any weight, its just like a gel paint, put on 2 coats.
I pretty much just put it on for wear resistance, on my other sled the paint was so nice and I figured it would get scratched up easily where your feet are, so the bedliner stuff might be more durable and not show the scratches.
Plus, I needed to make the tunnel black to go with rest of sled so this finish was what I was looking for. It really looks neat in person and with the yamaha braces and skidframe bolt plates being shiny black, breaks it up, looks pretty sharp.
shall report back on durability of it, although, shouldnt be too hard to touch up if it does get chipped or whatever, just rolled on.