Nitrous in near stock civic

Hi I'm new to this so stay with me.I just bought a 1994 Civic a few weeks ago.Right now its stock w/ a chip I'm told.I want to get a header and exhuast system.I've been thinking about Nitrous for it but I'm kinda concerned.I've heard nitrous will melt pistons and shatter the rings.Could I put it on a stock motor w/ a header and exhuast and be safe??How much could I use??How much ET will it drop me??I find out sunday what it runs stock(no exhuast yet).