Differential Locker Advice

I suggest you contact www.piranhaoffroad.com.au/

Rodger Faircloud, That's definitely what I was worried about looking at them. Are there many e lockers in Australia? From the looking I have done, most diff lockers are only avaliable in the US or similar. Are the Chinese brands you would find on ebay and alibaba that ship to Australia any good or should you stay away from them?

Maverick. Had a little bit of a look on their online store and doesn't look like they sell any sort of diff lockers for any car. Have you had experience with them getting diff lockers shipped in before or?

Any kind of auto locker is a compromise. They work in a fundamentally different way to a differential and make a significant difference to how the car drives on the road. I would only consider one in a car solely used off road.
There are some options on Alibaba and similar sites, my favourite of which is a torsen (Quaife style) limited slip diff with electric locker. You will also find ARB copies, but a lot of the cost of an ARB setup is the compressor and installation, so saving a few quid on the diffs themselves doesn't help a great deal.
I took the somewhat controversial route of welding my front diff and it's fantastic. If that sounds like something you'd consider, best to message me and I can give you more details. Open discussions about welding diffs never end well!

Re. front or rear, the rear axle is generally stronger so will handle the extra forces of being locked better, but locking the rear diff does reduce manoeuvrability. With a front locker you retain steering ability when it is engaged, but you are putting more stress on the CVs. Rear provides more outright grip going uphill, but front gives more control to pick your route.  There is also an argument that you are less likely to break CVs with the front axle locked as it prevents the common scenario of a raised wheel spinning up then stopping suddenly as it hits the ground.
Depending on the driving conditions, locking either could be preferable and newer 4x4s such as the Ford Bronco acknowledge this by giving the driver the ability to select each independently.