Nitrous express kits

Id like to know also. I have considered an entry level NX kit for my stroker 69 Swinger, but don't want to open a can of worms. What you read says "no problem", but I witnessed a nitrous backfire in the pits at Martin this last summer that says otherwise. Im assuming it either blew the carb or intake off the guys car and surely damaged the fiberglass hood. Issues like that would ruin it for me.