If your set on it mate, than here you go,
COMP Cams to suit V6 Ecotec - Mace Engineering Group
There is a video of a car with the stage 2 cam on that page. I have the stage 1 cam, and the exhaust sound is almost the same as the factory exhaust.
Just keep in mind a cam change is not just a matter of slotting in the cam, you will need new valve springs, retainers, collets, valve stem seals, lifters, maybe pushrods, new cam bearings, and probably a new double row timing chain.
Now I know some people will say not everything there is needed, but it is all the stuff that I would change just for piece of mind.
Oh and if you go the stage 2 or 3 you will need a torque converter to match or you won't get the most out of it, and it will take off sluggishly.