slide on camper

G'day Mark
Make sure you have a really effective anti sway bar on both the front and the back.
Also, if the ute has done a few km's then the rear wheel bearings may be a fair way through their life and may not like the constant load. New bearings might be a good idea for reliability. Cheaper than a failure somewhere.
Some advice from a spring manufacturer would be good to have so weight issues are covered.
Springs can't work without good shock absorbers and because of the extra weight/mass involved then they will have to match the load and springs in order to control it all.
These will be quite different to the std Commodore shocks.
Don't forget the front shocks as they receive the load under braking and some attention there may be necessary to maintain steering control under brakes.

Hello Mark m8,
the vs was the last of the commodores that you could fit pump up shocks if you go that way have separate air lines for each shock Bill.