Dan,
Is your ute a single or twin cab? I have a 130 single cab and have been through the same dramas. I bought the poly airs that go in the inner spring and the 1 st thing i did when i got back from my Simpson desert trip a couple years ago was pull them out as they are useless. I then bought the heaviest springs ARB make and put them in (without the inners) and they levelled the ride height but crappy ride (like a landbruiser) if lightly loaded. I have now just put in a full set of full air bags in the back and am impressed so far. In hindsite, rather than putting the heaviest ARB springs i should of put the heavy duty ones and a poly air to allow some adjustment.
Another thing to consider is your weight distribution and centre or gravity. My ute has a steel canopy on the back which is heavy plus 2 spares hanging off the back of that. That means there is a lot of weight hanging behind the rear axle. I always have to take care where i pack things, eg keep the weight forward and low as possible. How many people do you see touring/ travelling with the towbar dragging on the ground and 4 tonnes of crap on the roof rack.
Cheers Gaz

