Durability of a nitrous sprayed motor

[7000rpmisheaven]

Personally I think that power adders are cheating when you have done little else to an engine. But somebody once told me that in the world of racing there are cheaters and there are losers.
My question is about the durability of motors that on the bottle. Nitrous is something new to me, I haven't really studied how it works. It seems logical to me that if you are going to run a 150hp shot then you are putting that much more strain on your motor. I know that retarding the timing will be necsary for nitrous to work the best.
What are some common mistakes that people make when using nitrous. What damge can it cause.
What do you have to do to motor so that you can spray nitrous often with the least damage. What is the proper or best way to set this up.