Just to be clear on what my point(s) were is that if you open up that engine, and there is a problem with it later down the road, they are going to screwtinize whatever you've done very hard. To put it a different way, just because I added headers to my '02, I had the dealer pretty much start a witch hunt on me; I got the area GM service rep' involved, and he didn't help much either.
I'm not saying any of this to bash GM. If you think about it, any modifications you make push certain aspects of the car out of design parameters. Sure, there are safety factors the engineers have accounted for and engineered into the car, but talking cams means higher revs', which means sturdier valvetrain is necessary, the oil thickness and protection differs that from which the engine was tested under and tollerances may no longer be optimal, and blah blah blah. In another instance, I learned that, at least in the recent past, there have been programming to even protect the cats' from being over heated, so the PCM will actually adjust the air/fuel ratio to keep them from burning up. That can actually hurt performance a little but in the interest of keeping the emissions system healthy.
I'm no engineer nor have a tenth of the knowledge these people would have, however, I'd done enough research to begin to understand everything they take into account to deliver us a car that will last a long time. When someone goes and starts changing things, it throws a lot out of whack and just know that if you want to play, you gotta' pay. I'm sure nothing would really go wrong with adding a cam, in all seriousness, just keep in mind if something does, I wouldn't expect the dealer (especially in my experience) to be on your side.
I just wanted to clarify a little in the even I was unclear