Suspension upgrade

Air Bags is the way to go .. I assume you have a single rear wheel otherwise you would hardly ask for leaf spring upgrade ..

I have a dually GMC and have a 2" level lift in the front with dual shock hoops from Cognito Motorsports. I also have their pitman/idler support braces and tie rod sleeves to strengthen the steering .. in the rear I have airbags for additional support when I am fully loaded with the slide-on and the 4.5t boat trailer. All shocks are Bilstein - in the front 4 and 2 in the rear ... There are a few US accessory shops in the Brisbane area I had contacted before I actually purchased the vehicle and decided to import all the parts with it .. they usually stock stuff for older models, because they say that the demand for the latest model is low or non existent ...

If you primarily want to do something in the rear Firestone Airbags are my suggestion. If you can buy the model specific brackets here I don't know ..
I got some stuff from summitracing.com and had it shipped to the dealer where I purchased my vehicle ...

Mr. Airbag has the Firestones here in OZ but probably not the mounting brackets for the GMC ... expensive to ship because it's heavy and USPS does no sea shipments anymore ...

In the front I doubt you get anything here in OZ. Cognito is the way to go but
shipping is also expensive since they only ship UPS and the stuff is heavy ...

will cost you several hundred $ US to ship a front suspension upgrade by UPS.

You can ask Eagle Parts and other US suppliers here if they can order it for you because the have containers coming on a regular basis and it might turn out cheaper that way, but I seriously doubt they deal with Cognito ... but I can be wrong ... the prices I was quoted here were off quite a bit when one has the opportunity of free shipping with the vehicle ...

good luck with your venture
gmd

You purchased your truck in Gympie I guess... they are a bit pricey with parts though, although they are very helpful and friendly. I have a bit of a story with them but nothing for this forum and nothing for which they are at fault. Ask some parts importer first for a quote on the Airbags .. or go to a local ARB shop and check with them .. I have the Airbags (purchased in US) mounted by my local ARB dealer. They mount my stuff although they did not sell it. I do most things myself only the stuff where the hoist helps I have done for me ..

When I travel loaded up my truck is at it's limits.. not over though as many people are. I have 5.175t GVM and am pretty close to that when loaded. Thats the reason I have the airbags in the back and also the double shocks in the front. I did a good run on gravel and corrugations with my slide-on loaded (1300kg) and that was just ok although a bit soft in the front with the cabover putting a bit more weight on the front axle .. I also get a new bull bar from the states which will hold my milemarker winch and that is another 200kg in the front .. I expected that and this is why I had ordered the Cognito leveling kit with the dual shock hoop. I have not yet been out on rough roads with the new setup but it is a lot firmer with the double Bilstein .. I can not say anything about the shocks at this stage .. they seem ok .. did'nt really challenge them yet to see if they get overly hot or not .. I guess with two in the front that is not to be expected ..

The pitman/idler support is recommended with a lift and with rough road driving .. it keeps the steering firmer and does not let the ball joints wear that easy .. I do not have it installed yet ... Chad from Cognito is sending my right hand kit next week to LA where it goes in a container. Ask your importer if they can order it for you, or at least ship it for you. If they don't know about it they can ask me. Todd or Joel know me well. The braces and tirod sleeves will be US$300 shipping by UPS .. that is stiff and worth while looking for alternatives.

In order to raise your GVM I would just use airbags and not other helper springs because that would only make the ride firmer when you are empty .. and with airbags you can level from side to side if required .. I have a long range tank fitted and when filled with the watertank of the camper filled on the same side, the truck leans a little to the left .. with the airbags and separate control lines I can level it easily .. but thats an extra control switch and gauge.. you have to think about this if it is really worth it for you ..

If you only tow and dont carry heavy I would not worry about the front other than pitman/idler support and tirod sleeves ... the lift is just a bit for optics and if you really wanted LARGE tires like 19.5" or 22" rims or 35" tires .. I only done the shocks because of the weight the truck carries when loaded ..

if you need anything else let me know .. I have all the GM manuals on DVD ..
you can write to me at gmd@ozshops.com

regards
gmd