Several good brands out there...Many times ( not all the times) you see piston damage from running NOS could be a result of negligent NOS use or improper set up,or some type of delivery failure...
buy the best piston Money can buy BRC,Diamond,J&E,...ETC......abuse,set up your Nos improperly or have a malfunction in your fuel delivery or timing retard and you will have some high price ash trays...among other issues.
i know this was not your question (NOS SET UP)..However i wanted to share the fact many piston companies in the past have got a bad rap for selling less then desirable pistons when it was the operaters fault from sqaure one.....one of the reasons i am not in the parts business........
just know your stuff when setting up the NOS or get with someone that knws their stuff...is all i got to say...
Brian
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Bjuice..
"I'M YOUR HUCKLEBERRY ! "