Originally Posted by RC_Woody

so the pistons come with numbers
smallest holes start at 1 and go up to 5(biggest holes)

in 1 single pack of LOSB2909 you get two of each number.
#1 x 2
#2 x 2
...
#5 x 2
So to answer your question if you need to buy 1 or two packs... answer is depends.

Box stock all 4 shocks have the #3 piston.

If you want the ability to have more than 2 shocks to have the same pistons(assuming you don't want #3 pistons) then yes you need 2 packs. Otherwise 1 pack should be good. Of course they are cheap and it never hurts to have backups. So I don't think buying 2 packs would break you either, however IMOP not needed.

If you are trying Lane's or Dunford setup then you only need 1 pack, as you only need to change out the rear pistons to #4's.

-Woody