Yea,A nos kit on your set up would be a disaster.Having a stock stroke crank probably not welded is my guess isn't gonna help the problem of not being fast enough.With no override it's pointless to have it because you obviously have to shift,No sense in getting a kit if you have to pull the clutch in to shift.There's no time to really hit to the button long enough to get a good shot of nos before you have to shift again.You're crank will eventually separate and that again is another mess of repairs.As stated a descent nos kit will run you 4-500 and you could buy a set of ported cylinders or a 4 mill crank and a cool head for that price and see a hell of a lot more gain in hp and also be more usefull in the long run.
I only say this from personal experience kinda being in the same situation you are.I eventually ended up selling it and bought a 4 mill crank and an override.My advice to you is buy a set of ported cylinders and a cool head.You can easily find a good ported top end for under 5.You will be 100% happier with that route than getting a kit with your current set up.It's nice to say you have it but pointless if you can't get the full/best results of it.