Again, TF coils are tall - you'll end up with a 7.5-8" lift, NOT 6.5". (expect the TF 4" coils to give 5-5.5" on a 4door, + the 2.5" from the spacers) If that is what you want, then by all means, go for it. Personally, I'd go for less lift and add flat flares, but it's your jeep.

As far as the difference between them, compare the components. See which, if any, are missing from the 4" and go from there. And remember that you'll need both driveshafts. And don't expect that front D30 to last, so set moeny aside for lots of replacement parts, or look into an upgrade...



Here is some more reading material.

https://www.jk-forum.com/forums/show...-37-quot-Tires!

 

the teraflex 4 inch kit is more like a true 5 inches of lift .

 

Here is the only one I can find.