Ahh,the joys of making chocolate out of s##t(see factory set up)good for street....woefull for track.In my opinion a few of the guys have danced around it,so heres what i would do.
At least Pedders Red inserts
190-220lb front springs Cut down Gemini are good.
18mm front sway bar.

Rear The softest rear leaves you dare along with maybee Pedders Red again to match the front DEFINATLY no rear bar unless you are getting understeer.

Locked diff or a major fix of the slippery cause a slippery that spins up the un weighted wheel is about as handy as an ash tray on a Harley.

Finally a new set of Advans or Toyos,this set up could have you picking up front wheels whilst on the limit but can be tuned out at a later date.
Give Bob the Builder a call thats the best handling circuit ute around i'm aware of.....Why try and re invent the wheel?

Enjoy

to suggest a locker over his rebuilt lsd is nuts. ute's have far too stiff suspension in the rear from standard, it allows a higher pay load on the sales brochures, but in reality the car has zero traction in the rear until they are loaded up with 100 plus kg. e.g. my brother has a BT50 and refuses to drive it without the full disc to disc 80 series landcruiser diff sitting in the tray, far too uncomfortable and dangerous as it wont get traction and the brakes lock up constantly

and if he would rather put engine oil in his front shocks than buy new inserts he is probably not going to buy adjustable shocks non-adjustable will give him 90% of the improvement for 30% of the cost

another thing i was just thinking of is castor, pulling the front wheels forward has always done awesome things for turn in for me, just get some extra thread wound on to your castors and lock them up with nylock nuts either side, pretty much run as much castor as you can on a hill climb as i imagine there is lots of sharp turn ins

weight distribution is a good suggestion, the ute spare is in the ideal spot, under the back behind the axle, cant remember where your battery is though ange?

I think what you'll find is it is still actually putting some power down through the outside wheel, there's going to be inside rear lift and that wheel spinning, it's just not effective enough. I honestly reckon you are going to need softer rear springs to keep the rears on the ground a little better. You could _probably_ also benefit from an even thicker front sway bar, in absolute laymans terms, you could go thicker till it started to understeer on corner entry. Anyhing you do to stiffen the rear will lift the inside rear more.

The other thing I'd give _real_ serious thought to is weight distribution. Do ANYTHING you can to get more weight over the rears. Perhaps a rear mounted battery (which might make the tray/bed less useful for carrying stuff). I"m not sure where the spare mounts on the utes, but you might actually find retaining it, or locating it as far back as possible helps things.

This might be a very very very tiny difference, but if you can space the rears out wider a little, it might help. Guard clearance might make that a no-go anyway.

Given the stuff around I had with king springs (about 85% of the problems were with a local spring/susp shop, but ultimately the king springs weren't captive either) and the options I went through with them, I'd suggest cut down gemini front springs (I went with TX, pre RTS so linear rate springs) I don't know what hte spring rate is, but it is _definitely_ considerably higher than the king 120Y lowered HD ones, the material is way thicker (and it only takes a little to get the job done) not to mention they are cut down, so the coil count is in it's favour too) I'd suspect they are around double the std rate, or more, and around 1.5 times the spring rate (avg) of the king springs, which are I think 80/130 progressive or something around that.

You could also (if they aren't prohibitively expensive, which unfortunately they usually are) look at adjustable shocks for the rear, and MAYBE look at slightly increasing the bump stiffness and reducing the rebound stiffness, which _might_ help keep the rears planted. Problem is a lot of shocks are only adjustable on one of the two, or one adjustment affects both, or similar. You have to get more expensive to get proper two way adjustable ones. I'd absolutely do this as the last step, since it's the most expensive, and will work better if you attend to the other options discussed first, than if you just fitted them without other changes. If you have to go to that expense, get all the other things done too to make the most of every penny.

want to swap some 255 springs for some 190lb ones ;), rotor weighs less than an a series or L series.

coilover front is a great idea, as is neg camber. It will cost you a little bit but you might find you are bottoming out your shocks currently if they are standard height and you have lowered it this does nasty things to handling. If you choose a shorter shock and mod your struts to suit you'll have much more suspension travel and you can uprgrade your spring and shock at the same time. If you want a cheap out (non koni) i have some brand new standard z31 short shocks and some old height adjustable stuff with 255 springs i could work something out for you? then all you have is the rear end. soft rear suspension can help with traction powering out of corners - you do need both wheels turning tho

do the flip leaves dance ange, and new shock first- its a almost no cost option- try it and go from there. thats what development is all about

yeah i don't think you want softer suspension in the rear, i'd think just stiffer springs in the front. i'd like to think my ute is relatively good handling car and i'm pretty sure my rear springs are stock (never say never but i guess) and if anything i'd say it'd be nice to get it stiffer. sure softer springs will get you better drive out of corners but at the expense of making the rest of the handling a bit sloppier and increasing body roll. a perfect handling car is really stiff and will almost "skip" across the road even on sticky slicks (if you go to the extreme), a proper handling car will dance around corners on the brink of oversteer and understeer and when the tyres are cold won't do anything coz it's too stiff for the tyres to get grip. one thing to note though is that when you're not close to the limit a perfect handling car will feel like the biggest piece of crap, they really come alive the closer you get to the limit, opposite to a good road car which falls apart at 10/10ths.
i'd say a locker will really transform the car and would be one of the best improvements you could make to the car along with stiffer shocks and suspension.

if i jack the body up the rear drops 50mm

my rear springs are already reset lower. im a bit worried that taking the bottom leaf out might lower it furthur.

i know its only a helper spring but the top 3 leaves already seem to be sitting on it. hopefully the ride height
remains when i take it out. interesting point about reducing the roll in the rear though...

never thought about it that way.... i can see how it would help

i put the thick bottom ute spring on the top
flaten the spring pac out,lowerd car
no roll in the rear