I installed the 4" Zone and I'm pretty happy with it. I did add a adjustable front trac bar and a 1.25" coil spacer up front because of a heavy winch and bumper. I hate the transfercase drop so I will be adding a 1" motor mount spacer to limit the amount of transfercase drop. As it is right now I don't get vibes from the driveshaft.
I like Zone products I have been told that its bds without the lifetime warrenty.
Just to give you a little advice if you install this yourself soak all nuts bolts everything with pb blaster. You having a 2000 tj things are going to be rusty. If you have any question pm me.
I did the lift about a year ago did not get any sag. Ended up getting about 4.5" of lift 35"s fit with no issues.