Buying 6" equipment question

Hey guys, I tried searching for an answer to my question but the forums don't allow a search for the term 6" (or at least I don't know how to make it).

I am trying to line up a shopping list of what I need to buy when I finally pull the trigger on a lift kit. I say kit but I may try to piece it together buying parts separately. I am getting confused on some of the numbers though.

To get a 6" lift (drop bracket) what size coilovers and shocks do I need to buy? The only sizes I seem to see are 2", 2.5" and 3". Is it just a matter of preloading the COs?

And is there a way to make sure I am getting the right leaf pack and rear shocks?

Thanks for your patience with a noobie.

 

Two of the 6" kits, proComp and FabTech offer the 6" coilovers as an option. You can go to Alcan for 6" springs. (or any custom spring shops)