im trying to lift my 1997 2500 8 lug suburban 4 inches and put 36 all terrains on it. i want to do a suspension lift.

some questions

1.) do i need a add-a-leaf or new leaf springs?
3.) what are some links to good lifts and parts for the job ?
4.) would a lift suspension kit be a good idea? What kind of parts come in that?

any other advice is welcome.