17 years old, new to yotatech and I have a 1989 4runner that sags and has very little travel on the suspension in the back. I'm thinking of replacing the leaf springs but am also planning on getting a suspension lift soon. Should I do both or will the lift will take care of the sag by itself?

 

if you use whole new leafs in your lift then that solves your problem

 

Agree. Don't do blocks. It's only cosmetic. It will raise the rear but will give you no spring. No-cut Zuk mod is the way to go if you're planning a suspension lift in the near future, like1stgenyoda mentioned on separate post.
Good luck with the restore.