For a 4" lift to be done properly you'll need
- Adjustable rear upper control arms (used to set pinion angle)
- SYE if you don't have a Rubi
- CV driveshaft
- Adjustable trackbar for the front and preferably one on the back as well
- CV Trackbar relocation bracket to keep your trackbar from contacting the gas tank.
- extended front brake lines or relocate the stock ones
- Wheels with the appropriate backspacing for your new bigger/fatter tires (3.5" - 4" backspacing.
I'm probably forgetting some stuff and I'm sure other will chime in soon.
Best of luck on your build