boatcop1
Statistically, it would be VERY unlikely you would be denied warranted service due to aftermarket skids and a modest lift. I would avoid a diff drop lift because it remounts the diff and is considered a modification from their viewpoint.
Unfortunately, there are a few members here that are embittered by the fact that their claims were denied and use the boards here to vent. It's kind of a downer, but do not let this stop you from putting on "reasonable" mods for the trucks capabilities. Thirty-two inch tires are large enough for type of trails our trucks can handle. Also, a couple inches of add'l ground clearance and some belly protection should not get you into trouble. The cases where diffs were quickly replaced on trucks that had these modest lifts far out weigh those that were denied. This goes for all Nissan models that share these diffs.
Keep off the gas and let the traction controls do their job. Keep wheel spin to a minimum and you'll be fine.
Our club has many modified 2nd gens that have been running monthly (or more) for the last three years with only one casualty. In the case of this casualty the individuals has has two diffs and one transfer case replaced, all under warranty. Obviously, a case of driving style(?), yet it was still replaced by the dealer.