pretty much any nitrous kit can be adapted, usualy cheap foger kit (non-plate) will do just fine. How much it cost depends on what kit you buy, if its new or used , and from where. I picked up a used NitrousWorks kit for 245 shipped, wich is an awsome deal i believe! new kits usualy range from 400-600$.
I bought a used dry nos "import" kit off ebay. It was under 180 shipped, and included the bottle, solenoids, and fuel pressure safty switch, and 10lbs of nitrous which the dumb ass thought he should ship.
as said, anything that doesn't have a plate should work great. I would say a 75 shot isn't out of the question, but don't spray at low rpm's.
depends on what you set the jets at (and if its adjustable, i think most are). my kit came adjustable from 50 - 175hp shot, since mine is 'wet' its sposed to be safer, but from what ihave heard its a good idea to put in a better fuel pump when u start shooting around 100hp , both wet & dry. As they say ' you can run too rich many times, but too lean only once!'