I also think that this info is hard to find in one place on outers or similar.
Its easy to look at photos of heavily modified, large tyred cars and really want to build a radical car, but everyone starts somewhere and its important to get the first step heading the right way.
Before you go off road for the first time, here's the stuff to do/check:
Fit diff breathers. There are cheap/easy and expensive/hard ways. Remember that the environment under your car is harsh, fuel line or trans cooler line is the best hose to use. Garden hose or other PVC stuff will have a short life and a busted breather is worse than no breather at all. Here's some threads from outers.
http://carl.outerlimits4x4.com/viewtopic.php?t=127110
http://carl.outerlimits4x4.com/viewtopic.php?t=99469
The transfer can be done too but is a bit more involved - best done with the transfer apart.
Make sure your charging system works, you have a good battery clamp (it's well tied down) and solid terminals. I really like projecta brand satin brass-
http://www.projecta.com.au/catalogue/cid/50/asset_id/80
If your battery is stuffed, save some money up and buy the finest battery money can buy, an Optima. This will give you years and years of reliable service, and fits in a sierra tray without too much hassle.
If you alternator is stuffed, look to the Ford EL 100A upgrade, info here: http://carl.outerlimits4x4.com/viewtopic.php?t=79826 It is an excellent conversion, and cheaper than a reco Sierra alternator (with 1/2 the output)
If you're having trouble getting your starter to pull in, look at the starter relay upgrade, an easy DIY project.:
http://suzuki.off-road.com/suzuki/artic ... ?id=277618
Make sure the free wheeling hubs engage. To check this, put the car in 4WD and in gear, and jack up ONE front wheel. It should spin with the hubs in free. put the hub into "Lock" and the wheel should NOT spin freely.
Remember to buy a snatch strap, 2X 3.25 tonne rated shackles, a first aid kit and a fire extinguisher, and keep them handy. (especially the fire extinguisher - it must be able to be reached from the driver's seat, regardless of what's in the car or what angle it's on. If you need it, it will ALWAYS be in a hurry.
You can see the extinguisher in Greg's old car here. It's the best spot for one in a Sierra.
Speaking of fuel, so to speak, it seems that most sierras are getting to an age where the fuel system is giving trouble. Ihave seen lots of fuel pumps in cars from 89-91 starting to pack up, filters clogged and hoses starting to split. As the fuel pumps fail, they will work fine on the flat but the car will stall out badly and not restart on big hills. On almost any old/unknown sierra, I'd replace the fuel pump ( don't go electric, just a new stock one), lines throughout, (only a few dollars) and filter.
If you car doesn't have a fan shroud (many get discarded as they make a fan belt change hard) try and get hold of one from Suziworld or another wrecker source. A shroud will be the difference between an overheating sierra and a happy sierra off road.
As you can see, none of this is the glamour stuff, but a reliable car you can depend on to keep working is far more important than the big tyres or spot lights... or whatever.
NOW to the modifications.
First up, remove the front antisway bar and see how you like the handling. If you like it, leave it off, it will make the car work much better off road.
Lock the rear diff, however you can afford. Most expensive is the ARB airlocker (up to $1800 fitted, full retail) the cheapest is to weld your existing diff, but this is illegal and has some drawbacks.
Fit a 2" Body lift from Justcruzin' on outerlimits: http://carl.outerlimits4x4.com/viewtopic.php?t=135423 You'll want one eventually and everything else gets easier once you fit one.
Now you can look at gearing and tyres.
Personally, I'd look to 15X7" Speedy rims and 31 10.5 tyres such as MTZ's, Cooper STTs, Goodyear MTR's or similar.
As for gearing, go straight into the transfer case, and go fir transfer gears from any of the major US suppliers - Lowrange offroad, Trail Gear, Trail Tough. If you never want to go beyond 31's, maybe 4.9's or similar will be fine, but many of us have gone to 6.4's or something would be the go.
Set up like this, you'll have the best "bang for your buck" able to drive right up to hard trips, but still have a useful daily driver.
Note, I haven't mentioned suspension at all. In all honesty, suspension work can be a fair minefield but as laid out above, it won't add much capability, only add comfort. That doesn't mean it's a bad idea, only that it's complex and won't get you further or on more trips.
Just some thoughts. Hope it helps some prospective members.
Steve.
hahaha 
although you have proven that lifts aren't absolutely necessary.
