69 Firebird progress/brake upgrade

[av8or32]

I haven't posted in a while but I'm really making good progress on the bird. My car came to me with factory style discs (added by previous owner) I would like to upgrade to some nice slotted/crossdrilled rotors and calipers. My question is, what type of kit do I need to use to upgrade and is it required to change spindles? Should I upgrade to power brakes? I'm not planning on racing. I just want updated pieces. I'll be running 17" or 18" wheels up front and I'm planning on upgrading to discs on the rear. I've installed a Hotchkiss TVS so the car is lowered about 3" all the way around (if it even matters)