I have a sunroof in my G6 and had leaking from the drain hoses being disconnected. The amp went out because of water in the amp and I'm sure that's from when the sunroof leaked into my trunk.
Well if you make sure you tell them that its from the sunroof that was faulty, i would think they would have to fix it, because its the fault of another malfunctioning warranted part. Make sure you dont ask the dealer, you tell them! Any proof that its from that would help in your argument.
2006 G6 GT
Mods so far: Black arrow overlays, Chrome recessed grilles, Blue LED license plate light, Blue LED reverse lights, Smoked tails, 20% Tint all around, Red led's for the interior, White led dome and map lights.
Sound System: 4 Infinity Kappa component speakers, 2 Amps (950w total) and 2 10" Kenwood KFC subwoofers, 7" touch screen Pioneer DVD
Performance: Mobile 1 oil, Mobile 1 oil filter