holden rodeo diff

4WD Systems in Adelaide for the Lokka, about $600, the rear limited slip diff can be tightened, but I would leave that for a diff expert.

Yes you can tighten up the LSD, call your local diff place and ask for a price.
A lokka in the front works very well.
4wd systems have them for around the $600 to $650 mark, allow another $600 for someone to fit it. It may be more depending on what they find worn during the job.
If you do it yourself allow a couple of days.
Fitting the Lokka isnt all that hard IF you have a bit of mechanical aptitude and decent tools.
What is a pain is that you have to basically dismember the front end to remove the Diff, and you may have to machine up thrust washers to suit the clearences required by the instructions.
Also Isuzu use the outside surface of the axle as a bearing race for the needle bearing on the inside of the steering hub where the axle goes thru it , this little foilble can be expensive as it will require the replacement of the axle, the bearing and the seals around them and as they are usually dry of grease and only lubricated by mud/rust its a more than even money bet they're stuffed. As a further dig ONLY bloody Holden have the required bearings and seal$, ask me how I know :( .
That being said, the lokka on the front compensates for a lack of articulation quite well and it's well worth the effort.
A 2in lift, 245/75/16 tyres, a 2.5 inch exhaust and fuel pump compensator adjustment to suit the rodeos go quite well.
Good luck with it.