G'day mate - yes you are right about reigniting a hornets nest.
Ok my opinion only;
I think in all states it is against the law to interfere with the pollution control equipment on a vehicle. Therefore blocking the EGR plate makes NADS illegal.
It is also illegal to have a manual boost adjustment in the vehicle so this also makes NADS illegal. Not sure about catch cans but probably illegal. Anyway there are enough points to make the fitting of NADS illegal. But, you must remember that these laws were to prevent people turning street cars into road rockets and not much thought was ever given to the advantages hat may be given to engine longevity. If you are a box ticker, NADS mod are illegal.
New car warranty; Again if you are a boxticker, the vehicle has been illegally modified and therefor the warranty is void.
However, if you want to be a realist, not just a boxticker, IMO doing sensible mods that are good for the reliability and longevity of the motor, and do not turn the vehicle into a weapon are a good and acceptable idea. As for avoiding warranty by using the fact that the vehicle is NADS fitted would only be a means to an end for the particular person/dealer. If avoiding warranty is the aim there are many ways of doing it and that would just be a convenient one.
A couple of other points. Firstly we hear a lot about 3ltrs detonating, but often not the background of how they were used or abused. Secondly, people who do not have problems don't write that on forums. I would have to agree that too high a proportion of the early 3ltrs had issues, but they are over represented on the various forums because as I say people that don't have issues don't write in. Issues often gather their own momentum as they are agreed to in popular media as well. Recently on this forum a member wrote that his dads unmodified 3 ltr had turned over half a mill k. I guess if it blows now everyone will say "there goes another one".
Lastly, if your is a 2011 model, you don't really have to do anything legal or illegal to the motor to keep it safe.
If your Patrol has been treated properly and you continue to treat it properly you should get a good long life from it.
Me, Iv'e got a 2005 GU4 which is just out of the suspect range and going great at nearly 200000k. If it does break well I guess thems the breaks.LOL