Real Deal with Nitrous!

100hp is safe
But as a previous nitrous owner, i urge you not to waste your money on it.
It's absolutely no fun.
Nor is it that cheap, figure a nitrous kit to cost about $400, if you want or need any other gadgets to go with it, they are $100 each, like a bottle warmer, remote opener, purge kit, etc.
Then fills are expensive too, that's if you can even find a place to do it.
Then throw in the fact that in some states (at least nj) you need a license to carry it in the car, i forgot where i got mine way back, i think it was the health department.

Put your money into the H/C/I, it's the lowest maintaince, least chance of damaging your car, and gives you a freshly rebuilt top end.
The supercharger is cool and all, but stock heads will almost certainly blow a head gasket if you beat on the car. The boost will exploit every weakness in your engine.