Suspension question help!

[Angrywood]

I know this topic has been covered quite a bit over the years but i am unable to find some answers to my questions..... so please bare with me

I have a 62 C10 and just recently dropped the front with the torsion bars about 3 inches. Looks low enough for me for now. Ive been reading about drop spindles but if im reading it right then i would have to convert to disk brakes? Also, from dropping 3 inches do i need to change out the shock for one of the lowered shocks?

Second set of questions deals with the rear end. As of now im looking at getting the 4 inch lowering coil springs. Do i need to do anything else or just change the springs? Ive read some things about the trac bar and not sure if going 4 inches if i need to mess with that.

Thanks for the help