has no parasitic loss like superchargers.
Nitrous needs no modifications, no intercooler, etc. It can be added to a completely stock engine and makes power on demand at all RPM.
You can choose the power you want to add, from 50hp - 200hp (without mods)
When your not using it, the engine and tune are factory and will pass emissions testing.
There are some draw backs. You have to refill the tanks often and its easy to over use NoS and damage the motor and/or exhaust system. That being said it's a lot cheaper and easier to install and you get similar performance when you want it and better fuel economy when you don't use it.