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.
"It has been said that politics is the second oldest profession. I have learned that it bears a striking resemblance to the first." - Ronald Reagan
Now with my very own Tech2....YAY.