There are always many questions on DII suspension mods so here's the basic skinny, hopefully save some time searching thru threads.
You can boil down DII suspension into two basic categories, those which require no further modification, and those which will require some extras.
I. The no-further-modification category consistst mainly of OME springs/shocks, OME spring/Bilstein shock combos, or OEM HD spring/Bilstein or OME shock combos. There are other combinations, but these are the most common, and you get the idea. On a DII, any of these combinations WILL allow you to run tires up to size 265/75/16, though there are several other popular sizes run with these suspension combinations. Unlike a DI, you will not have to bend back rear quarterpanel 'flairs'. You will, however, experience rubbing on the front radius arms at full-turn, but nothing dramatic or unmanageable. If you are running stock bumper, you will probably want to cut away the bottom corners of the bumper, where the fog light housing is (or on some models where the plastic is) or you'll get rubbing from the front bumper as well. If you are upgrading suspension to go off-road, you'll want to make this very minor bumper modification anyway. Finally, you'll want to upgrade your steering damper along w/ the suspension (OME seems the most popular & widely used). Many kits come w/ the steering damper, or it can be purchased seperately.
*if you have rear SLS you have 2 options: trick the height sensor to run the SLS higher full-time to match front ride height, or purchase after-market SLS spacers available from several sources. I am partial to tricking the height, as it free - much cheaper depending on your technical skill. Also you'll look & feel funny with fully expanded air bags plus 2" of spacer.
2. The further-modification-necessary category: with these, you'll typically be looking at a "kit" that has been designed to take into consideration the additional requirements of a 3"+ lift. (Kits are available from several after-market companies, including LRO.com's sponsors.) These will generally include extended brake lines, extended ABS lines, longer bump stops, and possibly drive shafts. Some kits include modifications to the shock towers and various suspension brackets. Steering mods (other than dampers), radius arms, etc with lifts in DIIs greater than 2" have not been necessary until you get into 5" + territory. You will need to either remove sway bars, or fit sway bar disconnects, to take advantage of larger suspension lifts. (As I understand, sway bar disconnects available for XJs can be easily adapted to work in Discos.) Otherwise you've wasted your money on suspension that you can't take full advantage of. Furthermore, with the additional height, you'll experience dangerous & sphincter-clinch-inducing body roll off-road (the opposite, however, is true on-road,,,you'll feel pretty weird,,,but you're safer on-road w/out sway bars than off-road with sway bars, assuming a safe, Disco-friendly driving style). Finally, you'll encounter the challenge of what to do w/ the watts linkage, as referenced in a previous thread, which is a problem still being experimented with. You don't typically have to worry about axles until you look at adding tires greater than 33", or adding lockers. You are very unlikely to break an axle with TC/open diffs/CDL unless you take a direct hit from a rock,,and that's what the tires are for. With 3"+ suspension you'll eventually want to add gears, but that opens up a whole nother can of worms with lockers, etc. Bottom line with stock gears and larger tires is this: you will notice less engine braking on steep descents off-road & on-. This will result in using the brake more than you would have to normally off-road. On-road, the problem can be solved by down-shifting more often than you typically would. But off-road you'll have to apply some brake on steep descents where, stock, you could engine drag all the way down. Finally, you'll want to be more respectful than usualy of following distance & brake time/distance. This is not a major issue, but one of adjusted driving style and, as with any modified vehicle, heightened awareness at all times of your capabilities, unique 'feel', and constant vigilance in driving style. So your need for gears is not immediate. That being said, you'll probably have gears on your "to-do"/"to save for" list.
Hope this helps any newer DII owners or future thread-searchers. Thanks to Serg for a great forum.
