Oh and NO on the 520 conversion. expect half the life you got out of the steel sprocket and well cared 4 1/3rd less on the chain. .50 sec less in the 1/4 mile?
I have a 520 conversion kit that came with my bike when I bought it. It doesn't work with my extended swingarm, but with the stock swingarm it fits, and I have ran the bike a couple of times with it on there, but the fear of it breaking has always been in my mind when running it. I did not have any drop in ET or MPH in the 1/4, may be even a little quicker, but not enough to say for sure. The lighter chain and sprockets would take less energy to get them moving.
The yield strength on the chain is suppose to be higher than the stock chain, but would probabley not last as long because of the smaller contact area of the chain and sprockets.
Just my thoughts, as I didn't leave it on long enough to see.