Depends what wheel and what size tire you’re going with. I’ve seen members here run up to a 295/70/18 (34.3) stock without a level on stock wheel and offset. If you have an fx4 a 2 inch level will still leave some rake left so a 2.25 inch would be better. If you’re interested I do have a ready lift 2.25 inch leveling spacer set for sale.
I have a Lariat Sport. Max tow package. 4 door 6.5ft bed. Removed factory 1.25 (approx) rear block. truck sits perfect not unlevel at all. even with 700lbs in bed not unlevel.
Ford 22 wheels with Toyo AT3 295/55-22 and they dont rub one bit. Required a shim 1/8" spacer on front wheels to clear upper ball joint safely.
But if your questions is what you have to get or buy, is nothing. Just loosen rear axle u bolts. Have a floor jack and perhaps a jack stand. I didn't even remove my wheels. Once you remove factory lift block (between axle and leaf spring), and aline pins on springs to axle. Retorque in cross pattern the U bolts. I do not remember tq spec off hand and enjoy. Recheck U bolts in 100 miles or sooner. Someday I'll take better pictures of truck. Once I got it went right into winter here in North. Yet to roll windows or open sunroof...