Well note that torque is the enemy here, not horsepower. Nitrous usually makes a lot more torque than horsepower (like boost does) so that's why I'd go with the harder input and output shafts if you plan to use nitrous.

If you're 100% sure you're not going with nitrous and going to stay N/A... then you don't need the hardened input shaft, hardened input drum, but I'd still consider that output shaft for high speed kick downs to take advantage of that cam.

The other stuff is pretty much necessary lol

I'm happy to help so ya don't get bend with sand in the KY