/me hits the
nitro feverishly trying to win a race in "offroad"
Kidding aside, 1bad is right. My 75 shot lasted 3 weeks before going with 150... Nitrous is fun BUT if used improperly, you WILL f/u your car. Read up everything you can, dont cut any corners, and you can have a hell of a time with it.
Since you are carbed, it will be a little cheaper..not much.
I think the NOS kit is about $400
But you would want all the goodies with it too.
A remote bottle valve is VERY nice to have while on the street, you cant leave the bottle open all the time (kills the solinoids) so I would definatly get that if I were you.
You might want to look into getting a new clutch, and replace any weak link you might think you have in the drivetrain.
-ed