When running nitrous, be careful with coated pistons. My experience is with a big block Chevy, but coatings will keep heat from migrating down the rod where engine oil will cool and get rid of the heat. If the heat does not migrate it stays in the chamber where it can melt pistons. Machine shop talked a buddy of mine into coating pistons on a freshen of a proven combination that was taking a lot of nitrous, after the coating, it destroyed itself in just a couple passes. Only change was the coating, in doing some research we rebuilt it with out the coating and it was reliable again. Some said if we would have richened the setup, it would have not had a problem, but we did not have the money to experiment.