GU patrol....polybags for weight

Rlbye, the short answer is yes. I have polly air bags in the rear of my GU with a air line each and the valve on each side of the rear step upright.

With vehicle loaded put in enough air to bring it up level again, or slightly above(makes low beam a bit "low")

You must keep 8-10 psi in at all times when unladen.

Tony.

I have a GU with polyairs fitted, and they work well. Had them in my old GQ for over 10 years without a problem. I recall that the min pressure unladen is about 4 psi, but I believe that all you need is enough pressure in them to keep them securely located in the spring. When pumping up, the brochure says to note the unladen height, pump the bags up to max pressure (30 psi), load the vehicle, and drop the pressure till the correct ride height is obtained, rather than load the vehicle, then try to restore the ride height.
If you get them, make sure that the valves are fitted where YOU want them; recessed in the step is the best. Some installers like to put them in the easiest place for them to install; ie, in a place ready to get wiped out.

rlbye: I've got all the same equipment on a Landcruiser 80, and carry 120 litres water as well, and fitted Polyairs after a lot of heartache, and must say they are the best money's worth of equipment I have purchased.... all those 4wd 'places' put crap on them thinking I would buy their 2000 units and springs to match but they were wrong and I am so happy I could cry ! ... got them fitted at the outlet in Sydney and cannot say enough good words about them...they have had the Simpson, Fincke, Uluru, Gulf Track , Barkly Tableland and lots of woosie tracks in Victoria stuck up them and they are FANTASTIC !!!! ( I reckon you should buy them !)