just remember, the way that nitrous works is that when it is exposed to the high temp of your combustion chamber it breaks down releasing a great deal of oxygen to aid the combustion process. But, the more oxygen you introduce to the combustion chamber, the more gasoline that you will need to maintain a proper air fuel ratio. The moral of the story is this, you can strengthen the piss out of your rods pistons etc. but that probably wont save you from detonation. the obvious solution is to use a wet system. in case you dont already know (and sorry if you do already know and i am wasting your time), a wet system sprays extra fuel to go with the nitrous that you are introducing to the combustion chamber, thereby balancing the air fuel ratio. also, a direct port system is weel worth the extra expense because you can be sure that an equal amount of juice will find its way to each cylinder. Also get proper spark plugs. a secondary function of your spark plugs is to absorb ambient heat from the combustionj chamber. staock type plugs wont do the trick.
Example: my friend had a b-16 with a rod and piston combo that could withstand 500 + hp, but his spark plug blew up and little pieces of it bounced around inside his combustion chamber and scored the walls as well as screwed up his valves.