Hi Tony.
No the gearing will not do the job in the short term. In fact, if your budget is limited you'd be better with standard tyres and gearing rather than big tyres and standard gearing. There's a few reasons:
When you're talking about a 31" tyre, remember that even though it's small tyre by big car standards, it's a really big increase in size over a stock sierra tyre - 20%. that's equivalent to putting 37" tyres on a patrol or hilux and expecting it to drive OK.
Add to that that Suzuki gearing is pretty tall even standard, so adding 20% to tyre diameter does the following things:
You have to be really hard on the clutch off road.
You have to hit everything fast.
It's hard on the motor because it's always bogging down
You'll never get into 5th gear on the highway (unless you're going down hill)
The end result is that it gets hard to trust the car, and easy tracks start looking hard because as soon as its steep you're stressing out you need a run up, bounding all over the place and killing the clutch.
Adding a locker only makes this worse - the added traction is added load on the motor and makes good gearing even more important.
Victoria is really steep - you don't really get a choice to avoid steep tracks.
To fit 31" tyres, there's a few ways you can do it. A 2" body lift will clear 31" tyres with no other modifications. Here is a link to the best body lifts available for sierras:
http://www.auszookers.com/forum/viewtop ... 15&t=13126
You can avoid the body lift if you are willing to cut guards, space bumpstops, or some combination of both, and there are advantages in lower overall height (and the stability that brings) but they are much more work.
With an open front diff and a locker in the rear, the driveline should be very reliable other than normal wear and tear. If you add a locker to the front, you may start to find the front CV's are the weak point.
Remember though that the most important things to add to your car are recovery gear, a fire extinguisher and diff breathers. These will ensure you can look after yourself and save the diffs from damage by ingesting water.
I'm going to come straight out with the controversial calls:
If you go 4WDing alone, then by all means look into a winch, but if you intend to drive with the club, it's low on the priority list. In fact there's quite a few of us who have had winches in previous cars and don't run them any more. I'm not saying they aren't useful, but in a club trip scenario, it's no big deal. Bear in mind that the cost of a winch isn't just in the winch itself (which are now very cheap) but in the supporting alternator/battery/wiring, mounting and servicing to ensure its reliable and trustworthy. There's nothing more annoying that hanging on a tight winch line with a winch that won't work. It happens more than you'd imagine.
Unless you have fabrication skills and tools, and are pretty clued up on part design, I'm not going to suggest trying to independently mount a winch and bullbar. Much better to purchase a commercial bar like ARB, TSOR or JML gear, which will safely mount a winch.
Likewise, it's not a priority to have a UHF radio for club use. We use convoy procedure that doesn't require radio communication to work, and there's rarely much radio chatter on our trips. A small hand held is plenty for car-to-car communication without having to get out in the rain.
I'm going to make a suggestion as you've yet to buy your car. Consider finding a soft top sierra with a removable hard top rather than a factory (steel) hardtop car. There's a couple of good reasons to do this. Principally, soft tops are much, much harder to damage beyond feasible repair. From your desired modification list, it sounds like you are keen on more difficult terrain, and it's not out of the question that you might have a flop. Whilst these almost never result in much damage to a soft top car, it's quite easy to twist the roof of a hard top badly enough that the doors won't shut or the windscreen won't stay in. With a soft top, all the bodywork above the beltline is replaceable so this damage is only a minor inconvenience.
I know that sounds melodramatic, but I'm just suggesting this out of pragmatism - I've seen it happen a few times.
Secondly, when the weather is good, driving a soft top with the roof off is totally awesome. Visibility is much better, but you can also see and hear whats going on. In winter, you can replace the hard top and have a secure and warm car.
Just some thoughts.
Steve.
