As a post above eluded to, their are over 20 different spring rates for the JK platform. The variables determining the different usage is (to name a few) 2 door or 4 door, Sahara or X, dual top group, tow package etc etc. if you look in the back of the owners manual there is a few page spread of the different tow/GVWR weights for each model.

I would imagine if you were a 2 door owner looking for an inexpensive lift, I'd just make sure the springs came from a 4 door Rubi or Sahara with the dual top group & tow pkg.

Personally, I just bought the 2.5" TF when it was on mega sale 3 years ago but this spring swap is a Good cheap mod!

 

The Rubi springs aren't taller than the base springs, they just have a different compression rate, so it doesn't squat down as much. It still won't replace taller springs our spacers but can help.

 

My sahara, hard top towing group is pretty high, I need to get under and see what srpings it has.