Dont get heavy duty springs, if you ever have the ute unloaded it will be like driving an empty truck.
They use soft springs so it as a smoother ride when unloaded. There is alot of people who have utes with nothing in the back, or less than 250kg of stuff.
Get some bellow air bags. Adjustable to what you are carrying. Make sure they are the heavy duty ones.
Got them on my Dmax. From speaking to suspension places alot of people have them on their utes.
Alot of suspension places wouldn't put heavy duty springs on, when I was speaking to them.
I have a lift off tool box, weights around 750kg with all of my gear, so a big diffrence when its loaded up to when its empty.
I guess this is where the air bags come into their own, compared to heavy duty leafs.
I run the bags at 40-50psi normal then let all the air out when I just have camping gear in the back.