Get an rpm window switch, and you will need massive speed systems fuel rail adapter.
You can use any efi system, but get one that is advertised for sport compacts, ect because it's going to have smaller jets included.
The massive fuel rail adapter sandwiches between the fuel pressure sensor and the fuel rail. This aids in providing instant fuel pressure boost when the fuel is being fed to the solenoid for the nitrous kit. The sensor sees a drop in fuel pressure right away and compensates with the placement of massives fuel rail adapter. It's actally the same idea behind saleens kit, but saleen won't sell their adapter.
You should hook up a wide open throttle activated trigger switch. Then Tie in a rpm window switch which needs to be set at a minimum of 3,500 rpms and a maximum of around 6,000 rpms. This is important to help avoid fuel puddling ect ect.
For the window switch you'll need to buy a tach driver though.
A 50 shot on a 2.0 Dura will not be any problem at all. I am sure that the engine will handle fine even without any timing taken out via tuning. If you want to be safe you can fuel up with 93oct or better, and get a little bit larger jet for the fuel-this will richen the mixture up a little bit.
Yeah, just make sure you get the correct jets put in and that you set up your WOT switch correctly. Most self install error is a bad WOT switch install. You should also place a fuel pressure cutoff switch on the rail. I think that is cheaper than the alternative mentioned. You shouldn't have much fuel pressure drop with just a 50 shot but its cheap insurance. Also agree, go with a NX wet kit and get the Gen X upgrade. You will not be sorry.