Actually what little bit you are going to take off is of no performance gain. Now If I were to see where there was a lot taken off then I go into the mode of; OK what is going on here. Page 7 of the rule book.
I knew a guy who used those metal flake additives to seal up a leaking valve seal. In the end, he fused his exhaust manifold to the block because the SG of the oil with additives changes the heat transfer. I would not use the stuff if you can avoid it. If you do, get a flow check at room temp and do one at running temps - the reading shouldn't be higher than 4X the baseline.