Has anyone read this with a new GM?

No, but it is common knowledge. If you buy something and modify it you can not expect it to be warrantied, especially if you take it to the manufacturer with the mod in place. common sense

This is for good reason. After working at a performance shop, and witnessing the poor performance of the in house "tuner" (some jaca$$ with a lap-top and the know how of a ignorant teenager) I can see why GM would tell someone who had their computer re-tuned by an idiot that they would not warranty the motor. These re-calibrations can literally destroy a motor from the inside, not to mention severely affect the emissions performance of the car.

Many times people shop around and pick the cheapest shop they can find instead of ensuring that they are receiving a quality product. You could replace a clogged fuel filter with a short length of hose to get out of paying the extra 5 dollars for a new one. and it may even work better, (for a short time) but it wouldn't be good for the car. Why would a company who built and spent all the time to produce a good, sound product have to pay for the ignorance of the customer in their pursuit of ten extra horse-power? Modify at your own risk.

Not to bad mouth all mods. Just be aware that their are dumb apples out there ruining it for everyone.

If they don't show proof that the mods are causing the fault, they can't legally deny warranty. People need to know their rights. Why do people still buy GM products anyway?

suby its because they are great vehicles expecially the camaros and corvette's and they dont sound like they are faling apart like fords and imports. and plus if tooken care of they last a hell of a long time i have a 87 iroc-z camaro which has been pushed hard and tooken pretty good care of and runs perfect with 270k plus miles on her.