with any tuning method when you increase the H.P/Torque it puts a strain on the internals!
so build it as strong as you can afford
and you would be surprised at what a small squirt will do!!
I'm guessin that the shots of extra power would be worse for
an engine's longevity than a constant amount running thru
m8 i've run my engine on nitrous for three years and i haven't touch it! and three weeks ago i ran my best ever with a 11.38 @ 117mph so if you build it properly then no!
but if you put it on a old worn engine then what would you expect to happen
the same thing that if you tried to run more boost on a turbo'd engine