I'd say that the best bang for the buck in a YJ lift is the BDS 3.5" lift. It rides well, flexes pretty good, has a life time replacement warranty, and won't break the bank like some kits.
But that's just my opinion.
<font color=blue>If you're going with 4" of spring lift, your driveline/steering linkage will require modification. The most you could "spring-up" without extensive/expensive driveline/steering mods is prob 2.5"...
Then, get a 1" body lift. You can then maybe avoid lots of expensive mods, plus your ride will be better than on 4" springs..
<font color=blue> I don't know about body lifts... maybe just Energy. Just NOT Pro-comp!
RE: 2.5" lift... you're looking to go inexpensive: Probably Rancho or Big Dick Suspension (BDS)... BDS gives a GREAT warranty, and a great price... I don't know about it's ride. I have a Warn/Black Diamond 3.5", and its great, but I had to do extensive mods... the total kit, with new shackles/brake lines/pitman arm/shims/t-case lowering was 1500+, plus some new tools...
Well I can tell you about the ride on the BDS 2" kit, it's great. I have this kit on my YJ with a set of TrailMaster SSV's. I didn't have to use a t-case drop (but it did come with one), dropped pitman arm, or extended brake lines. I have had this kit for a couple of years and havn't seen any sag at all.
I agree with the 1" body lift maximum, and am planning on using one myself.
As for the cost of the BDS 3.5" kit, it was less than $600 but didn't include new shackles or brake lines.
I used JKS's 1 inch body lift. Worked great, haven't had any problems. When I get home tonight I'll send you a couple pages I wrote a while back about the different suspension lifts and what I've heard over time, and what I've experienced. If I forget, e-mail me at [email protected]...