Suspension Upgrade Feedback

Yes - we had standard 2" lift kit, (raised coils) and poly-air bags fitted at 15-20 psi; the tower in which the coil sits tore away from the chassis. The dealer thought it was covered by warranty but when they sent the photo through Nissan refused to cover it because they saw the after-market coils fitted.

The Airbags destroyed the coil tower Not the springs .
Even if you went another 2mm thicker on the wire diameter of the coil, it still wouldn't have damage the shassis like that. Unfortunately, too many people are talked into using air bags inside coils and these are the exact consequences of stopping a spring from being able to compress......something else usually will instead no-matter who the manufacturer of the vehicle is.
I had a co-worker that set off on his trip of a life time only to end up stranded in the desert with a bent diff housing on his Pajero ......caused by incorrectly inflated polyairs........polyair didn't pay for the recovery of camper and car or the replacement of a new diff housing and axle, and he certainly didn't ask Mitsubishi for it to be fixed under warranty either.

I would be expecting compensation from the installer or polyair, not Nissan.

This is an interesting point. Last year our NM Pajero had poly airbags fitted inside extremely heavy duty coils (approx 3-4mm thicker than standard, and 3" higher) and dragged a very heavy Cub Drover. The back seats had been taken out and fitted with home made camper box, fridge, 4 jerries of diesel and 4 10l containers of water. She was loaded, and so was the camper. Airbags were set at 20-30 psi, and we had no problems going on Canning Stock Route Wells 51-45 and 23-5, plus Rudall R National Park, Carnarvon Ranges and Tallewana track - we had no problems with our suspension or mono shell, which is not supposed to be as strong as a full chassis on a Nissan.

Because of this I'm not convinced the poly airbags are the problem - we know of instances where STOCK STANDARD Nissan ute chassis have torn. Ours started to tear somewhere between Mitchell and Windora - much better road than the CSR.

Nevertheless we will quiz the deal and Polyair. Appreciate your feedback.

Polyairs ARE the problem, The "Stock standard Ute would have Had the bumpstop plates broken off from overloading which compresses the suspension so harshly that the bump stops are smashed again and again into the bumpstop plate.
If it was standard with no poly airs inside the coils this would have definately been what had happenned.

The better solution would have been to have put up with thicker coils on the patrol that were higher than standard giving you more distance between bumpstop and bumpstop plate.

Unfortunately people try and market a quick fix load carrying solution like "polyairs" and then when the user takes the vehicle off the highway and into the tough stuff the wheels and axle cannot freely articulate up and down as they have a polyair shoved up inside them !
PS the pajero was an NM as well just like the one you described as having owned except it had standard coils with the poly airs inflated more to compensate.
This is just one example of another vehicle that has come to grief from the dredded airbag ( I owned a TD 2.8 NM myself for years)

I am only stating fact and simple Physics so if you can't grasp what I have been trying to get across , then good luck and happy welding!