I have the Full Traction 6" kit on my jeep and I'm wanting to put another inch or so on it and am looking at the tera flex 1.5" boost, but I am wondering what to do about the rear? How do I tell how much lift my shackles that came with the kit provide in comparison to the other companies out there without purchasing them? Is there a specific lenght of shackle that provides a certain lift amount? Anyone able to compare shackle lengths out there with aftermarkets? I'm wanting to find greaseable shackles that provide 1.5" more lift than the full traction kit provides. I'm toatlly lost about how to find that out. Thanks for the help.