I don't know the exact answer, but I would say that exhaust, CAI, and stuff like that wouldn't affect your warranty as your not really changing the overall build of your car. As in an exhaust doesn't actually make your engine rev higher, work harder, etc, it just allows it to unlock potential.
A tune though does actually make your car work differently to how Holden designed it. So I can reasonably see how they may use that as an excuse to refuse fixing or replacing items like engine, gearbox, diff, etc.
-Democracy must be something more than two wolves and a sheep voting on what to have for dinner.
James Bovard, Civil Libertarian (1994)
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P.J. O'Rourke, Civil Libertarian
-Government's view of the economy could be summed up in a few short Phrases: If it moves, tax it. If it keeps moving, regulate it. And if it stops moving, subsidize it.
Ronald Reagan (1986)